'Entertainment' is a sneering word applied - often tongue in cheek - to something which the speaker considers unworthy, beneath him or her, trivial, not 'serious' ...etc. Not just in music but art, films, books etc. Opera and the theatre are never considered entertainment being for the elite - except G&S, pantomimes etc. Is there an element of the emperor's new clothes here? You have to suffer, be intellectual or annoy people to understand non-entertainment. Jackie Collins is entertainment: James Joyce certainly not. The Beatles were entertainment: chain gang songs as recorded by Allan Lomax not.
Doc John