Thanks for the links, space. I've enjoyed them.
However, the premise of this thread is not that good music no longer exists, but that the mainstream has diminished in quality. It's within the confines of that segment that young people are first introduced to the world of music. As we all were. We all started out with easily-digestible cliches and simple themes.
But for those born before, say, the 80's, we also had the luxury of experiencing pop music as it underwent a long maturation phase. We were carried along as the Beatles graduated from "Please Please Me" to "I am the Walrus". We were exposed to the fusion of genres, to the rise of the virtuoso instrumentalist, to thematic concept albums. We were introduced to jazz, classical, African, Persian and Indian influences that opened the door to a world of music beyond Bill Haley and the Comets.
All that's still going on, just not in the mainstream of new pop. That segment's rapidly devolving. We're going to need a new Bill Haley to coax kids to once again explore the outer edges of the envelope. It could actually be Lady Gaga or Beyonce, I don't know. We can only wait and hope that eventually one of them will decide they have enough money already and become artists. It could kick off a trend.