I feel like we should be past the “Lucas’s treatments got dumped” discussion at this point. We know many of his ideas were the starting point for things in TFA (and TLJ to a lesser extent). The fact that they didn’t follow his treatments to the letter shouldn’t be a surprise to anyone. First of all, we don’t even know how detailed these treatments were, they could have been very vague and general. Second, it’s very rare that a film of this sort will follow an initial treatment exactly (just look at Lucas original treatment for The Star Wars). Things will obviously change and evolve, and eventually you see a domino effect where I imagine it would have been counterintuitive for someone working on Episode IX to try to go back to the treatments, now that they’re so far down a different path.

The only realistic way Lucas’s story for the trilogy could have made it to the screen was if Lucas remained involved past the treatment stage, but this is something we know he didn’t want to do.