Not to make attendance excuses (being a bad football program for 30+ years is enough to cause the problem), but it's tough to create a large fan base when you're competing with eight other D1 programs in the state (OSU, Miami, Cincy, Toledo, Akron, Bowling Green, Kent State, and Youngstown State). The closest major media market is Columbus, and you can't compete with Ohio State. Down the road the other directions are Marshall and WVU and Pitt is within a couple hours.
Everyone is raised an OSU fan then goes off to the other colleges in the state and a lot stay an OSU fan. I think part of the problem is the older alumni who went there when we were awful - they just don't care about OU football. As we have progressed so has the interest. Hopefully we can continue to build, but it's a challenge.