Regarding the GI thing; look at the baby boom and when it started; that should explain why no large arena big band venues remained. The Elvis thing I think was an attempt to cash in on the R&B music in a safe way. That music carried a lot of baggage so here comes Elvis; a nice clean cut kid who loves his mom. Now the interesting part here is the rise of jazz clubs in the 50's. How many young guys went to university on the G.I. bill; a lot. They made that whole smokey club atmosphere possible by patronising those places. If you think of radio and it's developement; you have to track the rise of advertising and the marketting juggernaut that was unleashed on us begginning in the 50's. The end of the depression and return of G.I.'s with combat pay and cheap mortgages. I am sure any graduate studies in pop culture major could explain this all to us.