I'm not sure this is true. It was always the case that these things were contextual and based a lot on how the artist/musician/author presented themselves. The whole idea of "selling out" is predicated on the assumption you have some high ground to give up, or at least that the action you are taking would undermine strongly held beliefs of your fan base.

When popularity swings more to (obviously) commercially driven output, there is plenty of selling, but less selling "out", as it were. The pendulum will likely swing again.