Oregon, OSU, WSU all less than 50K for football. For example, if San Jose expands to 50,000 plus, they could get Cal and Stanfurd to play there occasionally, and maybe other Pac-10 schools as well. The big attendance for those games will really boost average attendance. You can attract big-name teams to your place if you have a big arena. You'll get a big turnout for those games, and it will boost your average attendance.
Rice is a good example here.
Texas is willing to play the Owls at the Summit in Houston, but they won't play at 5,000-seat Autry Court on campus. Other name programs have probably told Rice the same thing.