Money first as well stated by many posters, but there is a larger variable that is coming on board and that is the new revamped "playoff" system in football. The details on qualifying for the top 4 spots (and eventually top 8) will drive the expansion of conferences eventually building to 16 team members. We have to wait for these details to be released, but soon you will see a "feeding frenzy" of major conferences trying to establish themselves at the top of the food chain. The ACC will become an irrelevent "bottom feeder" in football.