That’s kind of the thing, though. It’s hard to thread the needle and produce something that’s just mediocre enough to have mass appeal while still not being completely terrible, and the people who do largely do it by accident because they’re fuzzy on what people actually find appealing about their work. A Wizard of Earthsea is a way better book than Harry Potter and it’s not like Ursula K. LeGuin didn’t earn respect and acclaim in her lifetime, but it didn’t lead to a generational media juggernaut because it’s not merchandisable. JKR is exceptionally unexceptional and that’s exactly why she spends her time having twitter fights instead of breeding dancing llamas or winning krav maga tournaments.