Also, if there's a choice between making greater art which is less popular and profitable, or making lesser art which is more popular and profitable, selling ou

Also, if there's a choice between making greater art which is less popular and profitable, or making lesser art which is more popular and profitable, selling out is choosing to create the latter, whereas not selling out is choosing to create the former. Without having to know anything about art, if the artist persuades you that they are not "selling out" then they're persuading you that they're creating the best art possible i.e. you are consuming the best art possible i.e. you have great taste. Which feels great, so you buy more, which is the real reason why they're saying they're not selling out in the first place.