From what I've seen at the campgrounds we've been to, they are filled with people who view RV camping as a safer option for vacationing during Covid-19. Much more that than people living in them out of necessity.
It seems many private RV parks have plenty of filled sites. Different restrictions apply for the different types of places, campgrounds, rv parks, private, public, etc. The private ranch where I was for the past several months is open, although there are some concessions for COVID safety. On a daily basis, you'd never be aware of the craziness off the ranch. Some events such as concerts and owner dinner are canceled but river floats are on as well as BBQ after coming off the water.
On our trip to Oregon in late June & early July we did not have any problems booking sites at KOA course we did it two months before our trip. In Boise I wanted to stay a extra day but couldn't so headed toward Pendelton and tried to stay there no luck so continued on and wound up boondocking it next to the Columbia river. No charge no noise and all by ourselves.