Three years ago, the wife and I were USA touring and when arriving at the park gates at Mount Rainier, the attendant quoted a price, which I forget, but then asked if we were seniors. We are, so I said yes and, without checking where we were from, issued us each a $10 lifetime pass. I didn't know the rules on this, so went away happy that we had these passes now, but later, in a motel, studying the card, I saw they are only for US citizens. We didn't travel through any more parks on that ride, so I guess I have to thank all you kind American folks for partially subsidizing our visit to Rainier that day!
Upon returning home, I destroyed the cards, figuring I didn't need the hassle of a more alert attendant noticing that we shouldn't have them some day.
Regarding where the money from the fees are spent, I can attest that Rainier's fees certainly aren't spent on road upkeep, as that road through the park was atrocious.