Excellent points; nice summations of the topic, IMO 
I’d add that even IF an artist feels within himself that he is “selling out,” it’s a bit silly how many of us elevate this into some sort of crime. Sometimes you have to do what you have to do. To ply one’s craft for remuneration is not evil, it’s life, including situations where one is being paid by someone else – LIKE YOUR BOSS – to do it! Further…I don’t pay money to attend a Bangles concert to hear virtuosity and to be “challenged” musically; if I want that, I can go over to the University of Illinois New Music concerts and pay THEM to hear THAT.
At this point, I’m not sure anymore that the term “selling out” even has any legitimacy whatsoever. I do recognize, however, the inner turmoil that a person can feel when they feel they aren’t following their heart’s desire. My dad once told me, when I was a young teenager, that I needed to start doing what I HAD to do, instead of what I wanted to do. I think a worse fate than slightly prostituting one’s music would be not doing music at all. A guy who had been a successful insurance agent, but at age 40 quit and became a composer, told me “You either follow your Muse, or it will become your curse.” 