>>717868728
Whatever the Emperor saw of the future in the Warp while he was at Molech implies it was definitely not. It is likely a Gandalf with the One Ring scenario. It wouldn't be a great fate for humanity under a God of Perfect Order. The Emperor, ironically enough, always cherished and championed free will, at least conceptually, in the grand scale (just not for his stupid sons who just should do what they are fucking told because I know better damnit!). And given he would have seen things like the Tyranids eventual arrival, the awakening of the Necrons and that Orks can never be permanently subdued, it probably wasn't possible for humanity to ever recover from such a blow, let alone ever unite together again. After all, look at the Eldar. That alone should give you the answer to the question.