To me it's not entirely the type of music or musician, it's the intent. If you love Bach and Strause, then dedicating your life to playing that type of music is certainly worth it. And we've all heard classical music played with passion, and we all know how powerful and moving it can be. As for the boy bands, I've seen the kids who become that sort of thing (not only with music). It's often not their dream, but something their parents pushed on them. Now I'm not saying their isn't talent there; you can't fake stage presance, but if I can't hear sincerity in the music, I hear waste. Not only the lack of sincertiy, but hearing the same song structures, the same lyrical ideas, the same instrumentation and production over and over again. We're musicians folks, we hear this stuff, and I know it drives me nuts.
Mark Sandman did more on two strings played with a slide than most pop songs ever will. It's saddening that despite his brilliant songwriting, powerful lyrics, and unique vision he died in relative obscurity, and sure most of these folks will in time, but still their songs will get played for ever on hit radio stations.
I think the heart of this is that I think we all need to remember that pop culture is going to do whatever it's going to do. The record companys are going to capitalize on this regardless of what all of us think is ethical as far as music is concerned. Either our music fits in at the time or it doesn't. So someday soon the trends will change, and all kinds of pop stars are going to be thinking of new ways to sell themselfs. I don't know about you, but I'll still be doing what I love.

By the way, I think Nina Gordon and Joan Osborn are both killer singers, and they've both been picked up by the same sort of industry thing other pop stars get sloshed into.