I contend that if things continue at this rate, then there really will be only two types of musicians: the uber-mainstream and the hobbyists.

Before this decade of piracy, we had a swath of "middle class" musicians that had a fairly broad appeal, but as you said--were left of center and weren't ever going to be multi-platinum. This is the type of music I enjoyed. The Roots and their neo-soul bretheren, obviously, but also in other genres like boom bap hip hop and punk rock, both of which I ate up in my teen years.

Now those leftist type of acts are further and further getting marginalized and anyone with a spark of creativity that isn't in lock-step with the mainstream doesn't really have an outlet aside from playing as a hobby, and not everyone wants to work hard at their craft for beans and a few high fives.

I can't imagine how many great albums have never come to fruition because the motivation has been taken away.