I definitely get your point to where they were the first so called “grunge” band to get really popular in that era, which led to a whole different era. Curious if you think it would’ve happened anyway and they just happened to get big first? Regardless, they deserve credit for that. I just never really cared for them, and historically I think they are overrated by many.
I liked Pearl Jam and Live quite a bit back then. Enjoyed some of Soundgarden, Stone Temple Pilots, Alice In Chains well enough.
To answer, was Nirvana just the first to get big, or would it have happened, anyway.
The US music industry, is more about everything staying the same, and resistance to change. Why small independent labels exist. The decent bands you mentioned, were more of the slow natural progression away from the hairband period. Similar tones, but gone were the cheesy vox, more attention to integrity, and grit.(Alice in chains was initially a glam metal band. Re-formed, and started off trying to sound like sound garden...they were dubbed "kinder garden" in Seattle...cracked me up)
Nirvana was more of a 180 degree shift. Don't think anyone else could have done it, in the US. Take the Pixies(1987). U2 took them on tour, because everyone was talking about them in Europe. Bowie dubbed them, the most important U.S. band in 20 years... Too different for U.S. success.(although , their 1st reunion tour grossed more than the eagles reunion tour- all without air play.)
Nirvana managed to bring the reckless abandon, previously only available in punk, and some how, made it accessible. They managed to make it off of MTV's 120 minutes, into regular rotation. Also made it ok to be different, and pryed open the doors for bands like rhcp, Jane's addiction, pumpkins, etc...
Don't recall if I ever owned a Nirvana album. I agreed with Cobain, that when asked about some songs, he said, "it was , for all the world, a Pixies song". What I liked about them, was that they slammed the door shut, on the hair band era.
No offense to hair band guys. So many of the later bands were so bad, that many could no longer stand the decent ones.