The national parks are over-crowded. Arches had to close Memorial Weekend due to over capacity. When you have a resource of high demand sometimes you have to raise the price. 
I was out at Double Arch in Arches one crisp morning after a rain. It was quiet and the earth was deep red with smells of flowers and earth, and only a couple other people around. It was very peaceful. Then a busload of French tourists showed up and they all started yelling at the top of their lungs to hear the echo. It was brutal. Once my grandson and I had Delicate Arch all to ourselves one morning. It was almost spiritual. Then a huge group of Chinese women tourists all chattering in a high pitch showed up. We left it to them. 
Since the American taxpayer maintains the parks, how about we charge foreign tourists more than U.S. citizens?