First of all, please remember that music is marketed in the same basic process as any other product. What you see on the CD labels, commercials, advertisements and programs is designed to appeal to a specific audience. If the packaging appeals to a specific audience-if the marketing succeeds-then everyone involved in the production of the music wins. They make money, which is a good thing.
But, many times you will read a music critic blast a musician for "selling out", by which the critic usually means the musician has written music that appeals to a large number of people. This is "pop music", and a sure fire way to tell if someone's a sell out, as if the musician were a greedy charlatan instead of a true artist.