Hm, as I see it, if one goal is to ease yourself into it, the most recent version will generally still be the better option, since one of the areas improved with every release is accessibility/convenience/QoL features. And while new mechanics and content are added with every release, almost all of it ends up in the mid/late-game or special areas that you won't see until you're more experienced, anyway.
As for getting a feel for how development has progressed, certainly a superficial feel can be had by just going through the public changelog (each release has all the changelogs since Alpha 1), though I know what you mean about playing the game and actually experiencing the differences.
The further back you go, aside from the smaller world, fewer extra mechanics, and fewer accessibility options, definitely the biggest difference would be that Cogmind was
much harder . It has gradually gotten easier with each release, on many different levels. (This is intentional, as high-difficulty optional content will be added as development continues, though I'll admit the game has somewhat crossed the threshold into "slightly too easy" in Alpha 6 and will probably reverse course soonish.)
Alpha 1 was pretty damn hard!
Anyway, back to your point, bandwidth wouldn't be a big issue, though certainly it would take some more work to put together and make it available / maintain it. That said, as long as you're a registered owner (I can see you are--but I mean anyone else, too), I'd be happy to offer a download of all previous releases on an individual basis to those who request it. I can't imagine the demand would be huge at this point.
I probably couldn't offer to do this indefinitely, because it does take time (= money), but in the short-term while demand is low I could manage.