What makes avant-garde avant-garde?

[MalignD at aol.com]

<< An artist who co-opts commerce, in the sense that he creates using recipes 
which he knows will be successful (usually because others have already tried 
it and succeeded), is undermining and, finally, demeaning, his art. >>

Well, yes, I know what you mean, but where exactly are the boundaries one 
might try to push back?  Turning commerce on its ear--and I don't know what that 
would entail or how it would manifest itself--is the sort of idea that strikes 
me as a possible avant garde:  turning the art/commerce dichotomy inside out.