This is far from guaranteed, though: it's a nice quirk of baseball regulations that pitcher skill and batting skill can both be trained to provide about the same improvement over amateurs.

In other sports this doesn't hold in the same way: e.g. amateur soccer games tend to be higher scoring than at the professional level, because defence improves more with training than attacking does.

That said, fields where adversarial generative methods are useful have an inbuilt damping effect where gains on one side tend to cancel out gains on the other.