Competition improves consumer welfare if the competition is on features that improve consumer welfare.

Without referees, competition can simply be on lowering costs and providing cheaper service.

If demand is in-elastic (there’s only one Yosemite) then simply invoking competition isn’t going to be a solution.

Without referees with teeth, the market can easily optimize for profit without giving a damn about anything else.

They do. Xanterra.

I have family who worked for them at Yellowstone, Crater Lake, and Glacier NP. (They also have the concession at the Grand Canyon and Death Valley among others.)

Seemed like a fairly good company from what little I gathered.

There is competition, they took over the contract from Deleware North in 2014 IIRC.