Well typically employees at a college typically treat the facilities like their private country club. Instead of getting the family membership at the bouldering gym, just build a bouldering wall and now you can go anytime.

This could just be a case of the profit motive aligning with the good for society as a whole.

New buildings can house new students and academics which is good and also helps bring in more money in future.

New buildings also preserve the status of the university as a top institution - there is some level of competition for students and talented academics and if Harvard fell behind other universities it would be harder to bring in grants. Of course this is a good thing for the university but it's also good for any administrator who wants to preserve their pay.