lot of departments professors have good business options
Most professors are professors because they want to be professors, not for the money. I had several professors when I went to school who'd left business (and taken a significant pay cut) for a chance to teach and research, and I have a friend who's turned down job offers to almost double his salary just because he really likes the university world. Enough people are willing to 'pay' for the opportunity to work at universities by earning less money. Being an administrator at a university on the other hand isn't much different from being an administrator anywhere else and thus you have to pay them full market rates.
Most professors are professors because they want to be professors, not for the money. I had several professors when I went to school who'd left business (and taken a significant pay cut) for a chance to teach and research, and I have a friend who's turned down job offers to almost double his salary just because he really likes the university world. Enough people are willing to 'pay' for the opportunity to work at universities by earning less money. Being an administrator at a university on the other hand isn't much different from being an administrator anywhere else and thus you have to pay them full market rates.