I don’t think it’s out of the realm of possibility. IT 2 and Doctor Sleep are both getting extended cuts on home video, and with Endgame and Spider Man both getting rereleases with new footage, who knows what’s going to happen. Considering that none of the things I’ve mentioned above were asked for but still happened
This breaks down along the idea that extended/director’s cuts only happen because the audience asks for it. That’s not usually how that sort of thing happens, it’s not a supply/demand sort of deal for the most part. Often these sorts of things happen because it’s built into the contract signed with the studio before filming has started. That’s not always how it happens, but it frequently happens that the presence of extended/director’s cuts aren’t due to fandom requests, but from either the director’s requesting it of the studio, or the studio wishing to increase the profitability of the home video release (in those cases sometimes the Director doesn’t even really want the extended version out there but it’s out of their hands).
In the case of IT and Doctor Sleep, those extended cuts were part of the planning for those projects before filming even got underway - the directors knew they’d have an opportunity to go back and make changes to what they were aiming for theatrically, and now it’s happening. It’s not really comparable to this situation, especially since the studio in question there is Warner Bros, not Lucasfilm. IIRC, that was the same scenario with Lord of the Rings, although there it was more of a gamble - Jackson was shooting stuff he figured he’d put back on the home video release, it was basically a question of whether the film would be successful enough that the studio would then allow him to finish and release those cuts. Of course, they were, and Warner Bros/New Line was more than happy to extend the profitability of their home video dept during the double-dip era of DVD.
The two Marvel examples you pointed out were, IIRC, closer to “the studio wishing to increase profitability” and essentially putting deleted scenes/trailers at the end of the credits, not re-cutting the whole movie. The major difference between all those examples and this one is that there’s no indication from anyone, anywhere, that Abrams ever had a contingency like that in mind.
This whole “extended cut” nonsense is more than likely out of the realm of possibility simply because it depends on all the poorly-thought-out fan-fiction that goes along with it being true as a premise, in order for the “extended cut” to exist. The whole reason we’re even discussing the possibility is tied to a single Saltier Than Crait post that is fairly ridiculous, and supported by an unsourced, unverified report from a heretofore unheard of “news” site nobody knows anything about that is also ridiculous in its own way.