No, they paid $28 million for naming rights for a stadium, so their name will be mentioned every time there is a home game, across multiple newspapers, television stations, news programs, etc. If someone gave Ron Harper the million dollars, what additional value will be gained above and beyond what they purchased already? Getting to put his name and face on a billboard, or in a commercial? That doesn't carry nearly the same reach for value as your name being mentioned every time the arena is mentioned.
The value you are talking about is if they can woo some elite level players, there will be potentially more media coverage and more nationally televised games. But that is an incremental value, and it would need to prove out the ROI.