I don’t think they could release anything without Lucasfilm’s permission. That would probably extend even to ANH post-2020.
My thinking is that Disney might come to their senses and realize that profits shared with Fox from an OOT blu-ray is still way more money than the profits they’d share from yet another reissue of the 2011 discs.
Working for a household name global company myself, I just can’t see them thinking that long term i.e. waiting until 2020 (when none of them will likely still be in the current roles).
Rightly or wrongly, they’ll be thinking of profits in the next year or two, surely?