User blog comment:Twilight Despair 5/New Plots/@comment-79.115.75.253-20180523104839/@comment-74.132.82.188-20180523225054

Nope, I don´t. I mean, yes, it´s horrible and world-changing and all of that, but I was thinking of cataclysmic as more outside of their control and coming from outside of them. This situation, with AU Michael in our world, can be traced directly to a sequence of events that happened--if I remember correctly--before Billie died. Because they had to fight Amara, they -ok, Cas, I guess,  I don´t remember, released Lucifer. Because Lucifer was free, he impregnated Kelly. Because of that, Jack was born and he--or his birth--created the rift. And eventually Lucifer helped AU Michael through. So these events were already in motion by the time Billie died. I always interpreted it as more of some natural order disruption-- like a tsunami coming out of nowhere, not a progression of events that could be stopped had other decisions been made. So, say if all the people who had died between Julian dying and Billie becoming Death couldn´t go anywhere and had haunted Earth and attacked the living. That kind of thing. And something more immediate.

All of that said, I also suspect it was a throw-away line or one that could have introduced another plot line that they decided not to pursue.