There are some additional factors that make the situation not a pure prisoner’s dilemma, but there’s similarities. When you run into situations where you’re spending more and more to compete with others, which in turn makes them spend more and more, it’s not good for the participants. There are a couple common ways out of that: collusion and regulation.
There’s some regulation involved here, but there’s no way to actually limit NIL. That will always be an option for schools that want to go beyond the revenue sharing limits. I think what’s going on is that many/most schools are moving the NIL funds to the school because 1) they want to make sure they have enough money to reach the limit, and 2) they’re hoping other schools decide to primarily/entirely base NIL on the internal fund, making it a norm (tacit collusion). That’s my hope as well, though I’m sure the rich schools will still have NIL far in excess of the revenue sharing to avoid parity. I don’t know how many schools will find themselves unable to consistently afford the revenue sharing maximum