whats not proper music about broadway and opera? are there any good bands out today that put out good music? I can't think of any, all good music comes from the past when it actually meant something. again though the people that are on these shows don't get the chance to write their own music they have to sing well known songs that the show provides.
There is nothing stopping these bands with "proper music" to try out on the show and do some advertising for themselves.