I was a teenager in the early '90s, and I can tell you why "grunge" was both a success and a failure. In those days, you could listen to what is now called "terrestrial" radio or watch MTV (this is when MTV actually played music videos). That's how everyone got music, new and old.
At that time, popular music was pretty easily classified. You had classic rock, oldies, soft rock, and "modern" rock (more about that later) on the radio. MTV was very cutting edge for many reasons because they played rap, pop songs, metal, hard rock, punk, and "alternative" (it was called "college" rock by Rolling Stone in those days). Aside from rap and "alternative", most rock music was beginning to sound the same. Basically, a bunch of LA hair bands with a formula of that was a bit rock, a bit punk, and failing at both. Of course, they all had a programmed "power ballad" to increase their appeal. Most of the music was based upon image as much as sound, and both were poor. GNR kind of broke that mold, but not to any significant extent. Bands like Jane's Addiction and The Pixies never got on mainstream radio, and barely got on MTV.
Then came Nirvana. I remember the first time I saw "Smells like Teen Spirit" on MTV. It was actually on Headbanger's Ball. They looked and sounded like...your friends in their parent's garage. But they could write songs...well IMO. Granted, Alice In Chains was on MTV sooner, but they got REALLY popular after Nirvana hit. Regardless, these bands were unlike anything on the radio.
When I think of "grunge", I basically associate it with Nirvana, AIC, Soundgarden, Screaming Trees,and Pearl Jam. The first four are spectacular. Pearl Jam rode the wave and had catchy songs, but wasn't in the same class as the first four. But the attention got placed upon Seattle, and a lot of bands from the area got attention that probably wasn't earned. Then the labels got involved, and tons of bands were signed who could copy the sound. Those latter bands are what grunge became- prefab junk.
I'm not surprised that "grunge" now has a negative connotation. Most of it was crap. But for those of us that were alive at the time, it was special because it was a slap in the face to the music establishment. No flash, no image, just rock. I was living in Dallas at the time, and our local "grunge" bands were many, but the Toadies and Tripping Daisy stood out IMO as bands that wouldn't have been heard of outside of the area if it weren't for Nivanva et al. and deserved to be.
I think it's hard to relate to it now if you weren't aware of it then because music is much more accessible now. It was like the second coming of punk rock, except the bands could play their instruments a bit better.
