One thing Bill Hunt disregards in his latest post is that an OOT restoration might not be based on the o-neg.
It could be that, like Blade Runner, the o-neg will be used for the current version but other sources (like interpositives and separation masters) could be used for the unaltered versions. This would still produce something much better looking than any fan-restoration could hope to achieve with a 35mm print.
He also specifically mentions that they have no 4k restoration, which could mean that they have something at a lower resolution.