Does anybody get upset at, say, when a new design for a boardgame comes out? I remember when WotC released a version of Axis & Allies that didn't have enough pieces to play the game--that was major gripe, but I've seen or heard of many Axis & Allies players yell at each other about it.
On larger scale, I've never heard of Warhammer players debating over the differences between the editions of Warhammer Fantasy and Warhammer 40k. Games Workshop churns out another edition or army book. There's lots of grumbling, some threaten to quit the hobby, some even quit, but other than that die hard players pony up their cash without much debate.
Even with CCGs like Magic: The Gathering another edition comes out with whole new cards, essentially resetting the game--at least in the official sense. There's grumbling and complaints, but I have yet to see Magic players spout vitriol over editions of Magic like D&D players do over the various editions of D&D?
Do other RPGs even have edition wars?
As far as I can tell, D&D and its derivative are unique in this regard. Yes, other RPGs have GMs, referees, or whatever you want to call them. But only D&D has "Dungeon Master" as a trademark.
I think that little fact plays a key role in understanding what the Edition Wars are really about.