There has not been something really that groundbreaking to really shake up things -or perhaps it has, thinking of the OGL movement- but it is not that difficult to try to imagine and accept the premise of the thread. And the way of acceptance here is not something that you should really think too hard about. As Scribble noted there is not enough information for such a thing. The new game could be as awesome as you want it to be. The important thing is that it is something so much noticeable in the community as to make it interesting to consider about. This will vary from person to person of course. But it is something you can convince yourself to be thinkable and so to discuss about its plausible or rather possible consequences, according to each one's instincts.
Emphasis mine -- Look, I know what you're saying. But what you're saying is "What if there was an indie game, but it would be so perfectly tailored to me, and something I consider so groundbreaking, that it would have a huge impact on the community?"
The jump there is from "tailored to me" to "huge impact on the community". It's almost narcissistic to go down that path. None of us has a faceless mass, a throng that agrees with us, waiting off in the wings. People have opinions for many different reasons, and even when they match up they don't -- witness threads here where people who like 3.5 or 4e nearly end up arguing with each other about why it's good, even though they both agree it is good.
Yeesh, my head hearts. I dunno what to tell you -- I really only have the energy to care about whether or not a game exists that my current group can play, and will that do the job it purports to. There's no unified community I can concieve of, everyone has their own opinions, and something that's intended to appeal to more than one person is inevitably going to have compromises in it. The more it's intended to appeal to, the more compromises built in.
I understand your thought experiment, I just don't think that it provides useful results. Now, discussing what kind of directions RPGs might go to appeal to a larger market is a great question, so is "is 4e good for the hobby?', etc. etc, but this sort of just mashes a lot of questions together with so many assumptions that it's not particularly useful as is.