My family rented an RV and went around the country one summer. I remember that the thing broke down about multiple times in the month we had it. Including a few days spent in the town of Black Duck, MN while the local truck mechanic sourced a replacement transmission!
RV’s are heavy, complicated beasts, and I suspect that a lot of rentals aren’t super well maintained. Buy one in winter, fix it up, play with it for half a summer, then sell it in August.