What's your solution to parks like Zion that because of geographic constraints, only has 420 parking spaces but more than 2 million visitors per year? That is already 13 people per parking space per day (obviously much worse on weekends and less on weekdays). Your options are 1) charge people more 2) institute a permit system with a lottery or multi-year waiting list (this is what they do on the Colorado River through the Grand Canyon. How many people do you know that have rafted it?) 3) just let everyone's experience be ruined by more people than the park can handle. 4) Pave paradise and put up a parking lot.

Those are the options you have to pick. Given those are the options, number 1 seems pretty darn appealing.