Regarding ‘The Godfather, Part III’, the reason that the original theatrical cut has never been released in any format is contractual. Paramount had set the theatrical release date before shooting even started, and rushed every part of the process to meet that date. As the date was looming, Coppola realized he wasn’t going to finish editing the film. He had final cut, so he could’ve pushed to delay it, but he was only making the movie because he needed a hit, so he wanted to play ball with the studio. So he agreed to approve a cut for release with the understanding that by the time the video release came along, he would have finished editing, and that final version would be the only version of the film made available moving forward [at least until the recent “Coda” re-edit].