but I fail to see how all that changes my original point.

Motivation is what drives alladat. It's what causes them to experiment with new rhymes schemes, topics, wordplay, copy/study successful songwriting, etc. Money curbs motivation. I am not necessarily talking about pandering to the lowest dom for sales, although that is apart of it. I am saying that, for the most part, rappers rap because either they don't want a 9-5, they want the lifestyle, families to provide for, or they want women. Very rarely for the art (these days). Those are the core motivational factors that drive rappers.

It is my belief underground rappers (Pigeon John, Murs, KRS,CunninLynguists, etc.) rap for art. In turn, they tend not to be as monetarily successful. They usually stay on point for longer because that cup cannot runnth over...they are driven by divine purpose. They do, however, fall off eventually because they are human. It is often because they grow out of that particular method of creative expression or they become frustrated by shit rappers farting in their cornflakes © O_E

Like I said a while back. NO rappers is the same rapper he was 15 years ago. Just as NO athlete is the same athlete he/she was 15 years ago. Business or Science are about the only fields that stimulate the human brain for 20+ years.