I view National Parks as a sacrificial public land. Let them be overly crowded in order to keep all the amazing BLM, state parks, national forests/prairies, etc... special.
It's selfish and elitist to say, but I almost feel like it's better if places like Moab aren't publicized at all, and people just find out about it through word-of-mouth like I did. It takes some education to properly "leave no trace" in the back country, and I feel like that sort of works itself out when people discover the parks largely by being invited by someone who's already in the fold.
If the parks are going to be a more popular destination for the general public, then I think it is probably better to have a permit system both to regulate absolute numbers, and to require people to pass some kind of test or course about how to be a good citizen inside the park.
This kinda baffles me because it really should take a bare minimum of consideration. The basic rules are not overly difficult, right? Don't trample stuff. Dig a hole if shitting in the backcountry. Don't feed animals. Minimise your impact. Don't walk around playing music at everyone.
Parks have signs everywhere. Clear brochures with obvious info. What makes it so hard for people to understand and make that tiny amount of effort?
Of course, I'm also a big supporter of efforts to increase the size of national parks and monuments in the state as well (despite this administration's recent efforts). Preserving and regulating more wilderness would go a long way to hopefully mitigating this overcrowding issue.