Popular music keeps getting worse and worse, IMO. And for the record, I'm not one of those who prefers the popular music of his own generation (the 80's). I prefer the popular music of generations before mine. Virtually any of them.
Some hypotheses about why things are getting worse...
1. Increasingly sophisticated market analysis. The attitude seems to be: give them what they want, even if what they want is garbage. In fact, garbage is cheaper to produce, so all the better.
2. The prioritization of televisuality. Now beauty = talent. That is a new development over the past few decades, and a terrible disservice to music.
3. Proliferation of artists. Hard to find a needle in a haystack, especially a haystack of needles.
4. Cultural apathy. War? Corruption? Starvation? Screw it, American Idol starts in 5 minutes.
I'm sure there are lots of other reasons, but those are some likely ones that come to mind.
Bryon