It’s a recon all the way back to X-Men #1, vol. #1. And it really doesn’t work. Xavier had the dream or he didn’t. If he hedged his bets and half-a$$ed the formation of the X-Men, it still means Xavier never really believed in it.
The same goes with Magneto. Everything he’s done since just before or after — it kinda looks like before — X-Men #150, vol. 1, is also retconned. The original trial of Magneto, the original Inferno, the original issues #1-3, vol. 2, Genosha, ALL of it was supposedly some kind of long game to establish Krakoa.
Of course, none of this makes any sense. None of it works. Where’s the sense of recognition by Xavier of the meaning behind the Sentinels appearing in #14, vol. 1? Where’s Magneto’s foreknowledge of the Wild Sentinels coming to destroy Genosha, in New X-Men #114, vol. 1 (really X-Men vol. 2 — too much renumbering!)?
Moira X, Xavier and Magneto against the alien and apparently native forces of A.I. just doesn’t make sense outside of the context of the story Hickman was telling. I’m sure he would have resolved these issues if he had been allowed the chance, but instead it’s a lousy retcon that makes no sense when looked at how it fits into continuity, because it just does not fit.