I think I got to agree with that guy who said acid rock screwed up music back in '72.
What is the world is acid rock??? I vaguely associate the term with Jimi Hendrix, but other than that whatever it was was such a tiny subculture that it had no impact whatsoever on the music scene.
Music really started downhill when schools stopped teaching music due to the cost. Back in the 70's in grammar school (long before I took up guitar!), I took violin for three years - today there is hardly any public school with a music program like that, Kids grow up with no musical foundation, and no way to tell what is good from what is trite and repetitive. So we get thousands of thuggish, illiterate rap bands and thousands of Britney Spears clones.
There are great, musicianship-oriented rock bands out there like Dream Theater and Spock's Beard, but too many of today's listeners lack even the basic musical understanding to discern the difference between these groups and the dumbed down retreads the record companies are pushing on them.