"IT'S NOT ABOUT MUSIC,"
*proceeds to talk entirely about music*
It's the evolution of what's popular, my dude. Times change. What people enjoy, what's popular, what makes money, it all changes. Relatability. Young people want to feel like part of the in crowd. When young people start making music, and other young people like it, then it creates a trend. You like it or you're different. This goes on until the market is over saturated and someone takes a risk and does something new. The new thing sounds different and cool and becomes popular. Like I said before, this isn't a sign that MAH AMERICAN VALUESSS are going downhill, it's a sign that we're getting older and are no longer the one's being marketed to.
Your posts make you sound like you're not an American, which makes me question why you're so hung up on our culture in the first place, but I can guarantee you that even thirty years ago, people held the same opinion that you do now, just with different nouns. "In my day, we weren't listening to the Britney Spears and the Tupac and the Third Eye Blind. Music has gone way downhill! The Blair Witch Project isn't even shot professionally, our movies suck, too!"
But even back then, it just required some nuance and work on *your* part to find the things that correlate to your preferred niche. For my personal tastes, HEALTH, Nine Inch Nails, Reggie Snow, a lot of stuff Mike Shinoda is doing, the Deftones, etc. are ALL great, but if you pretend the top forty is all that exists, than, like always, you're going to get the most basic, watered down "McDonalds," products, to borrow your metaphor, that exist.
I'm not even ribbing you here, there's a LOT of cool media out put, you just need to know where to look for it.