I'm getting tired of with the length they've been on air with the increasing number of plot holes.
Photo of the road leading back toward guard shack.
Everybody's on board with it but actually turning in the script's a different thing so we'll see how everybody reacts to it.
In season 5, before Michael falls into the pit with Sam and Lucifer, Castiel molotovs Michael with holy fire and completely destroys his vessel.
Although unbeknownst to him at the time, as he thinks it is all real, Sam is actually going through mental experiences, where he first fights a soulless version of himself, kills it and absorbs its memories, a while later, he confronts a version of himself that recalls all of what happened to him the Cage, this version doesn't fight Sam, but warns him about the cost of remembering before allowing Sam to kill him.
Michael's more naive world view would explain why he didn't show up yet: instead of doing something on his own, he's trying to find Daddy.