That is not so. How do you figure there would be fewer choices in the scenario I mentioned above? As far as I can see, there would have been nothing to "lose" except the edition wars that would not have come into existence in the first place.
Well, off the top of my head, there'd be no Mutants and Masterminds or Spycraft, to name a couple, if 3e had come out from a different publisher. There wouldn't have been nearly enough incentive for other publishers to adopt the d20 system, it not really being compatible with D&D, so there'd be a slimmer pool of RPGs in the market.
There's nothing to "lose" from a lack of new games from the perspective of people who weren't going to play them anyway. But at the same time, there's not much to "lose" for them if new games or new versions of the current game come out. If you run a mean game, people will show up for it no matter what system you run -- and if they refuse to give it a try because they dislike a particular system so much, I hate to say it, but they probably wouldn't have been that happy in your game anyway.
However, since you think it is so, then here's a solution to please us both:
All the "your game must be my game" crowd can go bother White Wolf instead!
Who's saying "your game must be my game"? Nobody is advocating kicking down doors and replacing rulebooks. When we talk about why designers change things to suit the tastes of people who don't care for elements of a system, they're not changing "your" game. Your game is still right there. It's fine. They're changing their game.
As for bothering White Wolf -- well, people who want all Vampire to be their Vampire do. Often enough that we remind them as well (or really, other people will do it for us) that we don't have a secret police who mandates that people adopt the new system. If you're happy with the old one, fantastic: play it! If you didn't think that the four-roll combat system needed streamlining, then bear in mind that the one-roll system was designed for those who think it did.
"Waah! Vampire needs to be redesigned from the ground up to accommodate my Zamboni fetish!"
If enough people said that, I can assure you it'd actually get some serious consideration. (At the very least, to try to figure out what they were using Zambonis as a metaphor for.) If enough people want a particular thing, it's no longer about a personal fetish: you're very likely looking at something emerging out of actual play. It might be a dissatisfaction with how your fighter performs; it might be a serious problem with the vampire-combat-on-ice-skates subsystem.
Whether each individual problem needs to be fixed or not -- well, there's the controversy. But "change nothing and fire the players who want any change" is not the cut-and-dried optimal answer; it's only argued that way because people adhere to this hobby like unto a religion.