However, note that the Imperium doesn't have those technologies. When the Imperium can develop their own closed Waaagh! circuit, they can stop believing in the Emperor.
I'm truly, truly sorry. But that position no longer exists. And hasn't since around 1995-2000 when they started tidying up the Fluff.One of GW's saving graces, in my opinion, is their stance that "it's all right and it's all wrong". There is no cast-iron canon and that's one of the things that makes the setting fun.