Is there really nothing in your home right now you would be sad if someone took and just gave you the money you paid for it?
Even a digital copy of a movie may not be so easy to replace on the services I have access to.
Stores are not allowed to go home to people and take back the stuff they sold, even if they refund the price. Neither should a company that advertise “pay this price and own this movie” rather than “pay this price and rent it for an indeterminate time”.