1. It costs a lot of money to rename something like a school: new signage, new namecards, new letterheads, etc. etc. Money that could instead be used on education.

2. Once a school is named after a person, that significantly reduces the likelihood of a future donor who would only donate if their name were adopted.

Given the above actual cost and opportunity cost, some might find it reasonable to guess that schools only ever rename themselves after rich but less-well-known (i.e. not Nobel-prize-winning) people if the donation is contingent on it.