There's way more to it than that. You're not going to get this PoV very much out of a very specific forum/thread like this one, which is more or less devoted to contemporary, highly-detailed, highly-priced collectors' lines, but most toy collectors appreciate the nostalgia of "original" lines, the more "antique" aspect of vintage toys, the fact that the vast majority of toys before 1990 or so were not kept in pristine and/or unopened condition and are much more rare in mint condition, etc.
I have no information on actual numbers of collectors - whether there are more "new" collectors or more vintage ones, but you're not going to find the vast majority of the guys who prefer the old stuff in a thread like this, or even very active on forums like the .org. You're getting a very one-sided view/population online, most of the time.
This isn't even taking into account the trend we're seeing now with several lines, of companies releasing "new/updated" toys only to release a "better" version a couple years later, making that previous version obsolete to most. This is very common with Star Wars, comic book action figures of all kinds, Lego (mainly Star Wars, again), Transformers, increasingly with GI Joe, and Sideshow Hot Toys.
MOTU MAY be obscure enough that this is the exception. I, for one, can not fathom an improved line of classic He-man characters any time soon, if ever... But regardless, the originals ALWAYS remain collectible.
And as far as the playability aspect, vintage has it beat hands down simply because of the vehicles. Poseability and playability are not the same thing.
This, I 100% agree with. My nephews have a few MOTUC figures and they have held up quite well.
Goddess would probably be the only exception I can think of...