The $35,000 scholarship Derrick Rose received from Memphis pales in comparison to the actualities of what he brought the school in profits in his lone season at Memphis. If some car salesman wanted to put Rose in a commercial in February of 2008 and give him $40,000 for it, fundamentally (and beyond the emaciated "current rules basis" fallback argument) I'm not sure how that's any different than Roy Williams doing Coke commercials. In both examples, both are state-supported agents receiving compensation outside of the university they're aligned with. Memphis wouldn't be giving Rose money. A private business would be.
Further, it's funny to me that we allow for financial competition in every form of college academics, professional scholarship, professorship hiring practices, coaching, athletic programs, etc., but when it comes to a kid who catches a football? Nope. He gets no slice of the pie.
It's weird too. I was a TA at the school I got my MA from. If someone wanted to hire me for a commercial based on my scholarly abilities (or lack thereof), there would be no objection to it. But the second an athlete does it? Hellfire and damnation!!!!