I will happily quibble your quibble.
Quibble reverse card!
A better anology would be the Viking settlers of north america we know existed... where are they? Some are now suggesting that Viking DNA can be found in certain "native ameriacn" tribes. Were they wiped out or were they assimilated?
They were substantially wiped out, and the survivors returned to Scandinavia (Norway or Iceland, I forget which). They had a settlement in Newfoundland. There was constant war-peace-war-peace-war with the local Native Americans. The Vikings made the decision to leave after strife within their own ranks. The leader of the expedition was a noblewoman who had a temperament more suited to raiding than keeping the settlement together in vexing circumstances. There was some kind of conflict between her and other Vikings about the trouble the settlement was having and what she was going to do about it. It devolved into a shouting match and then she flew into a rage and killed some people. The rest of the Vikings lost faith in her leadership and decided to return home. The Vikings counted the expedition a failure, and sort of covered it up, probably because the noblewoman would've had to face consequences for the killings. An important reason the settlement didn't succeed is that the Vikings involved kept it secret. They wanted to exploit the new land to gain wealth for back home, rather than colonize and develop it. The settlement was more of a large forward operating base than a colony. As a result, there was very limited immigration and the Vikings never developed the strength to resist Native American attacks on a permanent basis.
Musical accompaniment:
"European" DNA in pre-Columbian Native Americans probably came from ancient Western Eurasian people (some branches of which IMO went on to migrate west and become the ancestors of Europeans), who migrated over the Bering Strait land bridge with ancient East Asian people. Who knows what happened 20,000 years ago.
Where in all the Mongoose Traveller Third Imperium corpus does it mention that every human world is a mixture of Vilani, Solomani, minor human race cultures left to stew for over two thousand years and produce cultures as widely different as those detailed in the Aramis subsector in the Traveller Adventure?
Weapons-grade counter-quibble:
Not every world, but the majority of worlds in the Imperium have cultures derived from the mixture of Vilani and Solomani cultures. Then there are the cultures of the minor human races and the minor alien races, many of which have some degree of influence from the Vilani culture of the Ziru Sirka and the Solomani culture of the Rule of Man and the Third Imperium. The canon history of the Third Imperium on the Traveller wiki and the MgT2e Third Imperium book support this. What these sources do not support is the conclusion that each or even most worlds have cultures different enough to prevent a common Imperial culture.
From Mg2e Third Imperium:
Imperial worlds do have some things in common: trade and the presence of the Imperial military and nobility. Each of these institutions imports ideas, styles of dress and cultural norms that are often mimicked by the societies of Imperial worlds, especially those more open to interstellar culture. Pg. 4.
Imperial culture embraces the judicious use of artificial intelligence to produce wondrous technologies and manage massive populations in the tens of billions. (This implies that there is an Imperial culture) pg. 6.
After the Solomani conquered the Ziru Sirka and declared the Rule of Man, the two human subspecies and their cultures became irrevocably intertwined. Pg. 7.
After thousands of years of coexistence, Vilani and Solomani have found common ground. Social and physical intermixing has created a hybrid in which tenets of both cultures are present. The divisions between them are as evident as they have always been but they have learned to cooperate, leveraging advantages of both cultures to make a better Imperium. Pg. 7.
A collection of worlds known as the League of Antares was established as a cultural region in order to placate the most resistant forces in the domain. Pg. 8. (A cultural region implies that the worlds of the League of Antares have a recognizably common culture.)
The Lancian and Amec Protectorate cultural regions were granted to preserve distinct cultures that had developed during the nearly two millennia of the Long Night. Pg. 8. (Again, the worlds of these regions have their own distinct cultures, but these cultures are related to each other).
The Luriani Cultural Association was similar. Pg. 8. (Minor human race, so it has its own culture).
The Vegan Autonomous District was given as a boon to the alien Vegans... Pg. 8. (Alien race with a common culture on its worlds).
The Sylean Worlds were established to honour the contributions of the Syleans, whose cultural principles and personal sacrifices were a crucial part of the foundation upon which the Imperium was built and maintained. Pg. 8. (Minor human race culture contributing significantly to Imperial culture).
(The Vilani) engaged in a long, largely unopposed expansion into the stars, first exploring and trading, and then consolidating and conquering the sophonts they encountered. Vilani culture adhered to a strict caste system that focused on tradition, conservatism and the cautious use of technology. The Ziru Sirka reached its apex in approximately -3500when it was composed of 15,000 star systems spread across 27 sectors of space. Pg. 59. (The Vilani imposed their culture and its caste system on the cultures they conquered, so 15,000 star systems had Vilani culture for 5,000 years.)
The Vilani had already encountered and integrated many human Minor Races during the expansion of their empire... Pg. 59. (Integrated, as in culturally assimilated).
The Terrans and Vilani began to intermix and new societies developed that featured elements of both cultures. Pg. 60.
Vilani colonists had settled and intermixed with the Syleans starting in approximately -9100. The Syleans were largely ignored and marginalised by the Vilani. After thousands of years of intermixing, there were few pureblood Syleans remaining but some isolated communities had maintained complete genetic purity.
Vilani culture had come to dominate the world and oppress its indigenous population during the era of the Ziru Sirka but Syleans still engaged in traditional cultural activities and practiced their own religions, often in secret. Pg. 63
Keshi was a rich agricultural world during the era of the Ziru Sirka and was heavily colonised by the Solomani after the Interstellar Wars. Pg. 65. (Keshi, the founding world of the Chanestin Kingdom, is populated by the descendants of Vilani and Solomani, and presumably, their cultures).
The once-proud Kingdom was integrated into the Imperium and so began a painful, centuries-long period of cultural and economic decline for their once-proud worlds. Pg. 67 (Cultural decline definition: "Cultural decline refers to the perceived
deterioration of shared values, traditions, and authentic artistic expression within a society,
often attributed to external influences, societal changes, or a diminishing of creative impulses. It isn't unreasonable to conclude that after a lost war and subsequent Imperial occupation, Chanestin culture was largely supplanted by Vilani-Solomani-Sylean culture of the fledgling Imperium.)
Cleon... vowed to leave Vilani social institutions intact. Pg. 71.
The colonies of the Spinward Marches, had grown and expanded to include more star systems, bumping up against and, in some cases, pushing out the previous inhabitants. Pg. 80. (The colonists had to come from somewhere, and were probably mostly Vilani, Solomani, or mixed.)
The fleet elements that carried out the Vargr Campaigns were largely drawn from Vland and Lishun because of their proximity to Corridor and the majority of their officers and crews were pureblood Vilani. Pg. 81 (And presumably culturally Vilani.)
The process was slow but inexorable, taking one or two star systems at a time and then providing incentives for Imperial citizens to repopulate vacated worlds, expanding outward until their borders pushed up against the larger Vargr polities. Settlements became colonies... Pg. 82. (More Solomani-Vilani-Imperial colonization and cultural imposition, not ancient 2000 year old indigenous cultures ).
...the Imperium established a strong foothold in Deneb and the Spinward Marches, pushing out Zhodani colonies on the spinward-coreward corner of the sector. (More colonization by Imperial Vilani-Solomani). Pg. 83.
(You know, for the all interstellar trade and travel collapsing during the Long Night, there sure a lot of jump capable pirates everywhere. I guess pirates all went to pirate college and majored in pirate physics and pirate naval architecture).
The spinward colonies continued to flourish with Regina growing in importance and becoming the capital of its subsector. Pg. 83.
Individual worlds were allowed to govern themselves as they saw fit, resulting in unique cultural and societal flavours. Pg. 86. (Again, flavors/variations, not a mosaic of incompatible mutually unintelligible cultures).
While the empire was composed of trillions of sophonts, including a multitude of Minor Races, it was still essentially governed by a Vilani-Solomani compact. The Rule of Man may have perished some two millennia earlier but the spectre of Solomani culture still hung over it (the Imperium) like a dark cloud. Pg. 94.
The people of the Arcturus Federation, Easter Concord, Vegan Polity, Dingir League and most importantly of all, the Old Earth Union, could hardly have known how much the far greater empire to coreward feared and dreaded a future in which the combined might of the Solomani Rim would be brought to bear against them... Pg. 95. (The Solomani Sphere is populated primarily by Solomani, and their culture(s) with some intermixing from Vilani culture).
Our homeworld was a place where Vilani and Solomani had mixed for thousands of years. Pg. 101.
...the Solomani attempted to regain lost territory in the Old Expanses only to be sharply rebuffed, especially on worlds with large Vilani populations. (And, presumably, Vilani culture.) Pg. 101.
...the Imperium had already been a hybrid state of Solomani, Vilani and, of course, Syleans even before Cleon’s declaration. Pg. 102. (And, presumably, their cultures.)
...the origins and power structure of the Third Imperium were still very much rooted in Solomani traditions and culture. Pg. 102.
The occupiers sought to integrate themselves with Terran culture, becoming Terrans themselves as best they could. Pg. 103.
Despite the presence of many human and alien races, the Vilani and Solomani have by far had the greatest impact on the (Core) sector. The Vilani first arrived approximately 7,500 years ago and called the sector Ukan. (So, 7,500 years of Vilani presence and 5,000 years of Vilani domination). Pg. 106.
After thousands of years of intermixing and the intercession of the Long Night, the Core is neither Vilani nor Solomani but somewhere in between. Pg. 107 (So, Core Sector is intermixed Vilani-Solomani culture).
Portions of two defeated empires – the Interstellar Confederacy and the Chanestin Kingdom –and other worlds retain some semblance of independence and a distinct cultural flavour but most have been fully integrated into the Imperium. Pg. 107. (Again, a semblance of cultural flavor, but fully integrated into Imperial Vilani-Solomani-Sylean culture).
The Apge subsector is dominated by the Apge system, which contains over 80 percent of the subsector’s inhabitants. The Apgeans are staunch traditionalists who favour a Vilani-style caste society in which everyone knows their place. Pg. 107. (80% of the subsector population favor Vilani culture).
During the Long Night, Apge reverted to its Vilani roots. Pg. 108.
The motto of the Perite subsector might very well be ‘Look to Spinward’. Regardless of its proximity to Capital, Perite has a distinctly Vilani flavour... During the Long Night, populations on many worlds collapsed; the societies that remained returned to the Vilani language, traditions and rituals that had guided their lives for thousands of years. Pg. 115.
The duke himself is of mixed origin but has adopted a Vilani surname in order to endear himself with the Vilani-majority population. Pg. 115.
The Imperial Navy’s 69th Fleet... Pg. 124. (I feel sorry for those guys).
As the Third Imperium came about, one of its key tenets was respecting Vilani culture and traditions. Pg. 127.
The molecular structure of Maeghen’s native plant life makes it indigestible for humans. Over thousands of years of habitation, the Vilani genetically altered select species to make them nutritious for humans. Pg. 136.
Minos was overlooked by the Vilani during the era of the Ziru Sirka due to its inconvenient location and lack of resources or life. It was eventually settled and developed by Solomani colonists. Pg. 136.
Dudinian culture is an extremist version of the Vilani caste system. Pg. 142.
Sanches... was annexed by the Terrans late in the Interstellar Wars, oppressed by military rule for centuries and was the capital of a Solomani-dominated pocket empire during much of the Long Night. Pg. 143.
Core contains 11 of the 25 worlds that form the Sylean Worlds cultural zone. These worlds were settled by pureblood Syleans and people of mixed Sylean blood after the formation of the Third Imperium. Pg. 149 (Founding members of the Imperium with a significant contribution to Imperial culture).
The Wayward Worlds... the schism did result in a distinct, non-Sylean culture that is still evident among these worlds to this day. Pg. 149. (A non-Sylean culture present on multiple worlds rather than each world have a different culture.)
The Syleans had deep cultural resentment of the Vilani after a millennium of oppression and were quick to shed the Vilani names of most of their worlds. Only Shudusham, which had already changed its name shortly after being contacted by the Sylean Federation, retained its name largely due to the presence of such a large Vilani population. Pg. 150.
Capital was once known as Sylea and has been inhabited by humans for hundreds of thousands of years. The Syleans, a human Minor Race, were seeded on the world by the Ancients. After thousands of years of intermixing with Vilani, Solomani and other human subspecies... Pg. 154.
Onon is an inhospitable world originally settled by the Vilani over 5,000 years ago. Pg. 158.
Rhylea... Sylean colonists built a cultural and religious refuge there. Pg. 159. (Sylean culture).
The Kaskii subsector... Most worlds in the subsector were barely populated when the Third Imperium was established... the Syleans... embarked upon an aggressive population expansion project, the fruit of which may be seen in the Kaskii subsector today. ...there are now over 48 billion Syleans in the subsector. Pg. 162. (Sylean culture, one of the founding influences of Imperial culture).
The Chant subsector currently has a population of about 13.7 billion. At its peak, it had over 14 times that. Chant has been continuously settled for over 7,000 years dating back to the original Vilani expansion into the Core... Pg. 186.
Dingtra (subsector) has not strayed far from its conservative Vilani heritage. Pg. 192.
The modern Ushba Sindi people are the inheritors of this conservationist approach. There are strict Vilani-style laws in place... Pg. 197.
Even after over 1,100 years of Imperial citizenship, the Chanestin people have clung to their cultural heritage and have found it difficult to assimilate. Pg. 222. (Here we have a distinct region culture different from Imperial culture, but the worlds of this region still have a common culture among each other).
After the Chanestin yolk was thrown off... Pg. 226. (Those Chanestin eggs, man. The yolks get all over the place.)
Saregon is the Core’s most populated subsector with 286 billion sophonts living on 39 worlds. Pg. 229. (It appears that the subsector's worlds share a common culture, but the text doesn't say which human populations settled the sector).