Because in my humble opinion he WOULD be good at it. I think he could schmooze for tons of cash. The OU donors are a tougher crowd than Iowa's, and most LOVED him. He hired and fired many assistants, showed loyalty and also showed balls to remove many close to him when needed. He remained close to the top for most of his coaching career at a powerhouse with a tough (but loyal) fan base and a tough history. He won, a ton. So he has a history to point towards as an example of how it can be done. He dealt with a changing world by standing with players against hate crimes, and also probably learned from not flat out kicking the kid off campus for knocking that girl out.
With all that being said, he ain't coming to Iowa to be Athletic Director, but it's fun to discuss during the doldrums of June in college football world.