Partially related: How come I can "purchase" 4K files on iTunes if there is no way for me to make a permanent backup of the movie (because I'm not allowed to download 4K files) which means I am dependent on the content not getting removed from iTunes or else my "purchase" just vanishes. For HD files the "purchase" label makes sense, because I can download and backup them. But for 4K, it's more like long-term rental.