Actually all those problems are precisely because NPS does not privatize instead once it figures out it can not provide basic services it grudgingly invites private players with very little freedom to run their business or pricing.
Edit: And this also totally misses the point of the parks to begin with. They're there not just to entertain visitors but to preserve these landscapes for posterity. Privatizing them would totally go against that. We don't need anymore land barons exploiting the masses and preventing them from experiencing the places they have a birthright to.