I guess that people who complains about 3e, 4e and (hypothetic) 4.5e don't play Warhammer 40.000, Warhammer Fantasy, Blood Bowl or almost any GW game.
In their games, new edition is something that invariably arrive every four/five years. New edition means new core book, and new army books, and a many new miniatures (as old minis aren't game-worthy anymore, the new ones designed to be better).
So every four years, GW player regularly rebuy most of their stuff. Because almost nobody use old edition.
And gamers do it, they see it as a normal part of gaming. Even if GW games are a lot more expensive than D&D. Different expectations, differents ways of seeing hobby, I guess.
Sorry for this semi-random rant...