My answers are: "yes," if using a broad definition of "selling out," but "no" if using a more restrictive definition. It was only trio-era Genesis that changed their sound to make hits (substantial hits; not small flukes like I Know What I Like). I would say that losing 2/5 of the band (especially those particular two) more more less created a new band. Though the Genesis sound did change gradually over time, IMO trio Genesis represented a fundamental change in the band and it was a change that quickly affected both the manner in which their music was made, and the intent of the final product. Was going from ATTWT to Abacab a "sellout?" I don't see it. One could say that that just got better at doing what they were already doing.