What's up with mainstream music?

Nobody in mainstream music makes any attempt to try neat musical techniques. It's all 4/4 house beats with 4/4 instrumentals laid over with vocals, which ae the primary focus of the song. Why does no one try even *simple* polyrhythms, polymetrics, diminished scales, atonal chords, time signature changes, etc.? all this stuff can be done without much thought, but it seems to me that mainstream musicians don't even try THAT stuff. If you want an example, listen to this: http://www.youtube.com/watch?v=5o4YJsPWf%E2%80%A6 He doesn't use all of those but he works with whole tones and polyrhythms and time changes alot in this song. Why can't people even try simpler versions of that? What's up with Lady Gaga? Or "Bratney" Spears? Or any one of a hundred funny-haired, goofy-named artists?