What do the audience really think of Frank's music?
Jon's music is quite bad, but I cannot honestly say that Frank's music is that much better -- a bit more complex and unusually perhaps, but just as lacking in melodic beauty and the lyrics sound just as contrived.
This is my personal (and subjective) taste of course, but therein lies the inherent problem of any film that relies on (the supposed quality of) artistic achievement to carry the point -- the audience might judge the art differently. Here the audience is supposed to be awed by Frank's genius, thereby looking past the fact that the group is completely dysfunctional socially, and recognizing the purity in the pursuit of their own kind of music as a superior way of life. However, for those who find Frank's music mediocre at best, the group is just a parody of the suffering artist cliche, their insularity mere self-indulgence, and their way of life no more valid than Jon's goal of writing music that is, well, more sharable with others. And the put down on Jon's music as *beep* is all the more annoying.
Or perhaps the director intentionally make Frank's music marginal, so as to make the point that art is ultimately personal rather than universal. However, this is undermined by having Jon's music comically bad. (Don's own song is quite decent by comparison.) And equating sharability with publicity just muddles the issue further.
All in all, this is still a rather amusing film. I just wish the music (Frank's as well as Jon's) were better.film; I just wish the music were better (for my taste).