Personally, I see ocean-going ships on Earth during the age of steam as the best analogue to the Traveller universe. There are no fast ways (airplanes) to get anywhere. If you want to go from Europe to America, you go to a big port and you take a ship from somewhere like Hamburg to somewhere like New York. There are a few big liners which would probably travel back and forth between profitable city (planet) pairs. If you wanted to get to a certain island in the Pacific, you might take a liner from Hamburg to Hong Kong, and then a tramp steamer that stopped at six other islands (planets) before it got to your destination. After your visit, you might wait weeks before the next tramp steamer came by take you back to "civilization." Did people travel around in those days, yes, but relatively few.
As an example, my great-grandfather served in the British Army. He was from Winchester and ended up travelling to India, Afghanistan and South Africa. He retired, volunteered for service in WWI, and then retired again. His wife, my great-grandmother never travelled more than 5 miles from the cottage where she was born. After WWI, my great-grandfather got a soldier's land grant in northern British Columbia, Canada. They packed up all their belongings, travelled to Portsmouth, boarded the SS Saxonia and sailed to Montreal. There, they took a three week train trip across Canada to northern BC. The settled the land and my great-grandmother never travelled more than 5 miles from that cottage. My great-grandfather was relatively well travelled (via his military career). My great-grandmother, not so much.
I agree, most people would be born, live and die on the same planet. There are those to whom travel is a great adventure and they would likely be the ones who got jobs where travel was part of the deal (military careers or things like merchants). I think these "Travellers" would be the distinct minority.
Think about your own friends and family, how many have travelled to other countries or continents? In the case of Europe, I am thinking of travelling outside of the area conveniently connected by trains. Myself (from Canada), I have travelled to Europe (two dozen times???), Middle East, Far East Asia, Caribbean, and Australia/New Zealand. I consider myself fairly well travelled. I still have not been to South America, Africa (except for Egypt which barely counts), or Antartica. That is only on my own "relatively" small world. The Third Imperium and other settled regions are huge by comparison.
- Kerry