Technically you have to move your site every 14 days on BLM land, though to your point that is not going to be enforced in some regions of the Mountain West. In some remote areas of Alaska, including the islands of the Inside Passage, there are small, informal off-the-grid permanent settlements on government land. If they aren’t causing trouble such that someone complains then it isn’t worth the government’s time to care.

In the wild parts of the US, even the government tends to adopt the “live and let live” ethos of that type of country.