For the record, Grunge did effectively remove Big Hair Rock from the forefront. And Rap Rock/Metal effectively forced the hand of AOR stations, resulting in many a switch to Classic Rock. I don't believe that either are even up for debate.
Kinda, but hair bands were dying out. As with all trends, it had been milked to the point of absurdity. Winger, Vixen...the end was coming, grunge or no grunge.
Grunge met the same fate. Nirvana and Pearl Jam were awesome, Smashing Pumpkins great, and then let's try to get a broader audience with the Gin Blossoms and off we go over the cliff.
The hair bands did themselves in. Grunge arose from a market need for new direction, which music always go through.
Starts off new and raw, then the suits come in and ruin it.
Though , really, since about 2002, I can't tell the difference between any of it...