Except the big difference now, compared with Genosha and other recent mutant states, is that their land is alive and sacred. As has been painstakingly set up by Hickman, mutants now have a literally limitless army* to defend against human oppressors, so there is no reason why they would ever abandon Krakoa to escape off-world.
*Plus, mutants will eventually have machines on their side, which is not even guesswork, since we've been shown that in X^3 Nimrod the Greater is Cerebro, and a few human specimens have been preserved in a zoo...