Let me preface what I say here with the fact that I have long been a fan of Nirvana. And how they changed the music industry with Nevermind was really significant.
But at the same time, the true creative output of the band was so short lived that I half chalk it up to anomaly as much as to genius. Back in the late 80s/early 90s when Nirvana opened for bands like Dinosaur Jr., I really didn't see what distinguished them at all from, say, Mudhoney. But today everyone knows Nirvana/Cobain and few even remember the likes of Mudhoney.