The void has always been regarded as a strange case because the boundary between it and the Source is already weak enough for voidsent to freely cross over at times, so I don't feel like it's something that can be written off entirely, especially given that the circumstances have somehow changed in recent times to be making Golbez pursue a scheme 10,000+ years in the making.

What the Ascians had once deemed impossible may no longer be such in the wake of all the changes that have come to the Source, though even if a rejoining is his endgame, I doubt it's actually going to fall through thanks to our intervention.