Insurance should be reasonable if you have a home you also insure.the assumption is it sits and is a vacation / weekend use thing and your homeowners covers liability. Up to and including snow birds for "some ins companies .. not all"
If you are s full timer and don't have a house your options are limited in companies that will write insurance. Of course it's more expensive as you don't have homeowners insurance and much if that cost is put into the RV .
I suspect many don't meet the standards in the policy like "in storage" or layup as my old company called it. 5 months a year etc. In fact I'd bet a good percentage have never read the policy !