Readers are willing to change. For every...epic fantasy fan who’s decided that it has to tread in Tolkien’s “riffing on British mythology” footsteps to merit the name, there are other readers who are looking for some sort of change in the genre. Still more who gave up on the genre when they thought it couldn’t change — all those readers can be lured back. Are being lured back, not just by me but by authors like Mark Charan Newton, Martha Wells, and others who are taking the toys of the old genre and finding new ways to play with them. Or just creating something new. Maybe there aren’t enough readers like this to make HBO create a miniseries based on the works they love, but there are certainly enough to revitalize the genre. I’d've had to change my name and start self-publishing by now if that wasn’t true.
So I say let the Ninalocas of the world have their tried-and-true cultural tropes. There’s good stuff in the medieval Europe milieu; nothing wrong with it. But I believe that as time passes this milieu will become a subset of epic fantasy — probably a big one, but still just one of a number of settings and situations that readers embrace. It’s already happening. So eventually there will be something in epic fantasy for everyone else who wants a sense of nostalgia and homecoming in the stuff they read.