College ball provides "blue chip" schools like Kansas a massive advantage over their competition. Bill Self in the NBA could end up like Nick Saban's abbreviate career at the Miami Dolphins. The playing field was leveled and suddenly, without a MASSIVE talent advantage, Saban didn't look like a coaching genius. (He literally quit his NFL coaching job midseason, I believe)
Self might be good on the next level, but I certainly understand why a college coach who gets the cream of the talent crop every year, might balk at developing an NBA team with a salary cap.