Board Thread:Warhammer 40k General Discussion/@comment-24821739-20140604204305/@comment-24944355-20140718004049

Before the long night there was no astronomican but humanity spread all over the galaxy. There was no true empire though as travel was too long and difficult to maintain a galaxy wide empire. But even given that there was widespread communication and travel and many mini empires like Ultramar.

So when the astronomican fails travel through the warp will still be possible (specially if emps smacks down the chaos gods) but will be too difficult to maintain a galaxy wide empire. The empire will collapse into mini empires and single system polities that will be vulnerable to Orks, Tyranids, Eldar, Necron, Tau and Chaos incursions with only the stongest remnants being able to survive.

What I think the Emperor intends is to build up his power in the warp as much as he can and then shortly before the golden throne finally fails to unleash the surviving Primarchs to stabelise and strengthen the empire long enough to smack back and weaken the other factions. Then the Emperor will lay the smack down on the chaos gods, weaken them and maybe close the great warp rifts like the Eye of Terror. After which any primarchs still living will form the foundation of a new empire, probably around Ultramar.