I'll ditto dontpanicbobby on that. There is no substitute for having your own personal drm-free copies and some sort of back-up copy of your media. Apple has traditionally been tight with drm and that's why I've always avoided their stuff and iTunes. It's how they lock people into their walled garden. They kind of gave way with music but it's still a bit of a tedious enough process to deter the average Joe. Movies are unfortunately still one realm that no one wants to give up their rights on. (Not the MPAA which means neither does Apple or Google, for that matter.)
If you like a movie enough to own it, buy a physical copy and rip a version to watch on your device. You get to choose how good the quality is and how much space it takes up. I love me some comedy but it rarely needs to be HD for the humor to come through versus something created to be a stunning visual masterpiece.
It sucks but the sooner you break that chain, the better off you'll be. It's ok to rent something you might only watch once or twice but if you really like it, you owe it to yourself to own a physical copy for safe keeping.
