I haven't compared them side by side, but is the charcter generation in Explorer's and Nerchant's the same as the core rule book - have to go check now...
Any changes would be extremely small and not rules-based.
So a couple of years out at minimum... hmmm 2027, why does that ring a bell?
Unlikely. It
is an obvious date, and it
was discussed, but doing an Update book just because of an anniversary... does not really sit right with me. An Update Core Rulebook will come out when it is needed, and not before. Plus, work would have to start next year, so really not that far off.
An anniversary cover, however... that might be a thing. We'll have to see how the print runs fall.
How can I find out if a new system is useful and popular if I don't have the book with the 3 pages? Putting these updates in JTAS would be an alternative solution to the compendium, unless you moved JTAS to a more regular periodical - 4 issues per year, 2... offer a subscription model to fund it.
It is certainly an idea, but given that we tend to print things when they are ready as opposed to strict deadlines... I am not sure this would properly work
Forum members are usually very kind in copying snippets of new rules into threads when asked, if that is allowed as fair use (which is appears to be since I don't recall a single instance of you asking anyone to delete something) why not just have a shared folder or a pinned forum post where such snippets can be easily found? Such a collection may actually help authors keep on top of current rules.
I am not not saying this couldn't be a thing

However, Effort vs. Effect we are generally talking about really minor rules, often limited to specific areas of Charted Space... I can see the value of what you are proposing but I am not persuaded that it is something that should be enacted with haste.
Slightly Longer Answer: This might tie into something else that is being tinkered with, along the lines of a digital tools set for Traveller. However, that is a project that is somewhat ballooning, and it has many questions that at the moment we do not have good answers for (not least being do we want to blow six figures on something that a good portion of which would not be charged for to users - I mean, it would be seriously cool, but...).
Lots of things in the works, and what you are proposing is one of them. Just need to get round blocks into square holes, and then get all the ducks waddling in a vaguely straight line.
(Now beginning to understand why WotC used to have two people on its Spine Design Team...).