You're getting lost in the english and inferring an active advocacy there common use does not imply. (...)
Let me stop you here, Hulk, because you're sailing away to the seas of OT. Anyway, my English might be shitty, but my reasoning is rock solid.
You're presenting the case like there's something that has be done, like there's some
we need to get done and you're reducing it to a choice. Please don't deny it, you said it for yourself. The problem is, that you're building your reasoning upon very limited selection of possibilities - you're reducing it to either/or case, even when there are truckloads of alternative scenarios. Event the itself selection is flawed - you're treating RPG as a monolithic entity, even thought it's fragmented and features very different games, coming from different sectors of the hobby, (each sector "under the protection" of entirely different breed of developers and players, each with their own opinions, tastes and needs), some better suited for certain situation, better accustomed to evolution and others not so much, if at all. This, in turn results with the reality where you can't simply say "RPGs are becoming". No.
So,
there are no choices, only possibilities. It's not that everyone/anyone out there has to take the side and do something about what you have in mind.
Things are gonna evolve in their own way and pace and there's not much about it that might be done, because once things become popular, they no longer evolve in a single, predictable way.
So. Sit, enjoy, write an adventure or two, play some, and don't you worry about the Big Picture.
As far as the dangers of mainstream, you're kidding, right? All new games are WFRP3? Got news for ya, that's already happened.
Not quite. People produce plenty of games that follow "you need a few friends, charsheets, pencils and a few dice; beer: optional" old routine, in contrast to "you need plenty of figurines, dem fancy custom made things we call dicelatorariums, a massive diorama rivaling in size and price with those taken from world's most popular skirmish game, handmade, platinum coated one-use charsheets resembling small games on their own, and 1000s $ worth additional collectibles to play
you all meet in an inn-type adventures, because that's true RPG, gib money nao" - which is, more or less, the concept behind WHFRP 3rd.
This might change, given the rise in popularity, because where's popularity, there's money.
Pick a major IP that has an RPG..now name one that isn't a "define OOC mechanic as roleplaying" narrative shitshow.
WFRP 3rd isn't about narrativism, this isn't the thread about narrativism, and I'm not the right person to discuss narrativism, because frankly, the only thing I give a damn about isn't what games uses which approach, only whether it's good or not.