The acquisition of Fox absolutely makes a difference. It wasn’t released before because Lucas was in charge and didn’t want to.
The acquisition of Fox made no difference at all, because Fox’s distribution deal had nothing to do with Lucas’ unwillingness to release it (although he DID release it while Fox was still distributing the films). Fox never had a say in what version of the films would be released, and there was no reason for them to get in the way of whatever version was released, because it was all the same to them.
Releasing any restoration would be an enormous money maker, and Fox owning distribution rights means that Disney would only get a small percentage of those potential profits.
You’re vastly overestimating how much of a financial draw “The original versions” would be. The audience for “the original versions” is very niche. This sucks (especially since I’m part of that niche and would love the opportunity to spend my money on it) but further - Fox owning distribution rights didn’t mean Disney only got a small percentage. You’ve got that reversed. The smaller percentage was actually Fox’s, and Fox didn’t mind having those distribution rights because even a small percentage of Star Wars money is nice, especially when you don’t have to do much work to get them.
Disney isn’t releasing the original versions (or hasn’t since they took ownership) primarily because they just don’t want to. It’s a sign of respect to Lucas. It’s basically been confirmed, multiple times now, that they’re not putting an “original versions” release out because they don’t want to do it if Lucas isn’t cool with it. It’s not a contractual thing, it’s not a money thing. It’s just that they consider the 2011 blu-ray versions the “canon” versions and they’re moving on from there.
That doesn’t mean the originals won’t be released ever, most likely as an “alternate version” as a bonus feature. It just means they want to make sure Lucas is cool with them doing it first. Maybe he is now (I wouldn’t be surprised if he’s in full “screw it” mode currently) maybe he won’t be until later. Maybe he never will be while he’s still around. But the originals not being released has never had anything to do with who owned the distribution rights.