There are still some good bands out there but not like it was.
Rock bands became convinced by the record labels to produce ballads and top 40 crap in the late 80's and they got away from making good music. MTV and the radio stations wouldn't play it anymore. Same thing for Heavy Metal, it gave way to the stupid Hair Bands for their mainstream appeal.
-The David Lee Roth version of Van Halen became the cheesy Sammie Hagar synthesizer version.
-Aerosmith made bad songs for bad movies.
-Heavy Metal gave way to Faster Pussycat, Kix, Poisson, and that other stupid hair band shit.
-Same thing for Grunge rock - it started with Alice in Chains, Soundgarden, Pearl Jam, etc, and it became Limp Bizkit, Creed and Nickelback.