I know what he means, I think, and I even floated that theory myself.
We know that PoX spins directly out of the nation of Krakoa, which we have only seen in the 10th TL, which is HoX, as confirmed with the many notes and references to Moira X.
That being said, we've seen nothing at all in the 6th TL, and that could be a pretty big macguffin.