U of C is already an elite academic school. They don't need sports to draw students. Schools not in U of C's class have to compete for students, and a top football or basketball program can make them stand out from other schools.
Notre Dame was a tiny, struggling school until football put them on the map and now they are an elite school. Schools like Louisville and Florida State have improved their academic standing as they made their way up from the old Metro Conference all the way to the ACC.