I am just about 30, so I was not around in the 70s, but I have heard enough 'classic rock' to make me want to puke. I hate all that crap from the 70s. Lyrically, at least the stuff that is STILL on the radio, everything is so simple and repetitive. Sure, I guess there were some great guitarists, but I just can't take it anymore. Throw in the obvious, disco (which really did start the techno of today- not my thing, but many people are into it), and you have a decade of music that is just not my thing.
I understand that the 80s were also lyrically irrelevant, but at least punkrock really exploded in the 80s and now it is a very thoughtful, intelligent genre. The problem with today's music is everybody is making albums and it is watering down music that is actually good.