Here's the simple explanation of why Lucas allows the OT to be released in P/S: studio pressure. It has been Fox's policy to offer both Widescreen and Fullscreen versions of all its hot releases for a couple of years now. When the film is short enough, they'll put them on the same disc; when it isn't, they'll opt for dual releases. Since Fox is handling the OT, even if Lucas does not want to offer both, he does anyway. As John Carpenter put it in the commentary on The Fog, "Let the idiots have their pan and scan."