USC has 11 national championships, Iowa has one. USC has 7 Heisman winners Iowa has one. Zillions more draft picks and All-Americans. USC also in the 2nd largest TV market, but the Hawkeyes will get $23 million more in TV money PER YEAR. That's why.
This issue is say Purdue has a coach USC wants (Jeff Brohm). With an extra $23 million per year, Purdue can do a lot to try to keep him home. USC may not be able to compete with that kind of extra cash. It'll be worse for assistants.