Its a problem in the sense that it happens rarely but theres some absolute horror stories. I can see why some people might want the house taken care of by a live in caretaker until they can rent it or move in.
The US federal minimum wage for someone for 24hrs 7 days a week is like $1200ish dollars a week, but you’re providing housing but not in a traditional sense, but they would be expected to do basic maintenance chores, then who pays the utilities?, etc, etc.
Im just saying that the idea is viable but you would have to do a LOT of legal legwork on a state by state basis to keep everything fair and above board for all parties.
Housesitting is already a thing, but what makes this context different is the open-endedness of it. To make it work there would probably have to be a bonus payment for successful move out after agreed upon notice and extra for short notice. The landlord might also have to provide basic furnishing so that the caretaker can moveout more easily when a proper tenant comes along.