If the Fox/Disney situation is all that's holding up a restored OOT then we're definitely not screwed. That will resolve itself eventually, even if it's not until 2020.* To me there is way too much money to be made by both corporations for it not to happen. In any event, it's certainly out of George's control now.
Like SilverWook said, we're doing a pretty good job of preserving the older versions all by ourselves.
*Speaking of which, if Disney will still have to pay for Ep4, is Fox really gonna charge them any less than they would for all six movies? There might not be a point in waiting.