Did you ever hear the tragedy of Star Wars: Revenge of the Sith Ultimate Edition? Wait, it's not a tragedy, but a fan edit combining prequel-era projects? Oh.
Writer/director Rian Johnson revealed that he was working on this aspect of Star Wars: The Last Jedi until the final days before the film had to be delivered.
When a director like Steven Spielberg (who also executive produced The Mask of Zorro) talks about the future of the film industry, you would do well to listen.