"The National Park Service is dedicated to
conserving unimpaired the natural and cultural resources and values of the National Park System for the enjoyment, education, and inspiration of this and future generations."
https://www.nps.gov/orgs/1955/our-mission-and-role.htm
Now that I'm retired, and have the time to visit the parks, I find that I enjoy camping in the national forests much more.
The price is about the same.
There is usually not cell service, and never wifi available.
The campsites are always larger in the national forest.
The hookup situation is about the same. There are no hookups. Potable water and a pit toilet is available. The national parks usually have flush toilets at campgrounds.
The only thing for sale in the national forest is firewood.
As far as camping goes, the forest service does a much better job. If the national parks convert their campgrounds to RV parks, I don't see how that would be "conserving unimpaired the natural and cultural resources..." It would make it easier for me to decide not to camp in the national parks.
The national parks are places to be inspired by natural and cultural resources. RV hookups, wifi, cell service, gift shops, etc. do not provide inspiration from natural and cultural resources that are unique to NPS lands.
EDIT And my snarky response: just like privatizing housing for the military has turned out to be great, so do it for the national parks too.