Not that crazy. The cost of storing the film—even 2 hour features—is dwarfed by the rest of the production costs. You can afford a dedicated HDD when you're done.
This will at some point in the future invert.
The cost to generate a future kind of film from some template (script, characters, art choices, etc in some kind of source file) won't be much more than the cost to store it.
When this happens, perhaps we will cache the results but later dump them. Assuming storage costs don't drop faster and more significantly.
Maybe 30 years?
Edit: Lots of downvotes. I'm a filmmaker, I've made lots of photons-on-glass films. Most of us are experimenting with this tech and aren't thumbing our noses at it like people outside our industry. We don't really have a choice but to adapt, and I find it funny that casual observers on the outside are so morally opposed. It's actually an incredible tool for pitching and has utility for some SFX, compositing, and B-roll shots today. It's really going to help mid market and below, for films that don't have Disney budgets.
Well, hopefully two.