Why have I never heard discussion of different rates for non-residents? State parks do it. I don’t think it’s nationalistic to say that if you don’t pay taxes towards the park, you should pay more to visit it. Especially considering that flights to get there are an order of magnitude more expensive than entry fees, the parks should be making some of that money.
My counterpoint is even if it doesn’t reduce crowds, at least the parks will be making 20x more revenue, so they can improve infrastructure to handle the crowds.