Well, as a reality check, even the soundtrack of a 1hr movie would be 50x floppy size (~50MB vs 1MB) if MP3 compressed.
I guess where this sort of generative video "compression" is headed is that the video would be the prompt, and you'd need a 100GB decoder (model) to render it.
No doubt one could fit a prompt to generate a movie similar to something specific in a floppy size ("dude gets stuck on mars, grows potatoes in his own shit"). However, 1MB is only enough to hold the words of a book, and one could imagine 100's of movie adaptations (i.e. visualizing the "prompt") of any given book that would all be radically different, so it seems a prompt of this size would only be enough to generate one of these "prompt movie adaptations".