Having a couple of young children, and what at least seems like ten thousand toys, I have an informed point of view on this--kids have lots of stuff because we, as a culture, have lots of stuff. Some kids are obsessed with their toys, some(and more than you'd think), really don't care that much about them. That's all.

The boredom, anger, lack of motivation--which there is a lot of, definitely, has nothing to do with the stuff itself--some of it comes from neglect; as in kids who don't get the attention that they need(and often are given "stuff" to compensate), some comes because kids are taught to think "inside the box" and are taught not to use their imagination, some because kids are constantly put into structured situations that are convenient for adults, but not really "kid friendly", and some because kids with outdoor personalities are shut up indoors all the time--

It *is* all a consequence of our affluent lifestyle, or at least our culture's preoccupation with the value of stuff, and co-incident disregard for the value of anything else-

One other thing, and that is that the demands of a middle class, materialistic lifestyle are at odds with being creative, particularly as related to music, and I can speak to that from direct experience, as well.