So here's my prediction for season 8...

[snarklyboojum]

As far as I can figure it, the only reason to bring Bobby back as a ghost only to have him leave again the way he did was for the delivery of the line: "And when it's your time... go."

Sam takes this lesson to heart and doesn't obsess over bringing Dean back, as we've seen him do before. After trying everything he knows how to do he attempts to move on with his life, maybe even finding a girl and "settling down".

Dean and Cas return from purgatory via mysterious circumstances or even under their own power (I'm working on a theory about how going there in their bodies is different than going after death, shh) to find Sam working through the idyllic life he wished for Dean after his own fall, to mixed results. How will this be different for Sam than it was for Dean? How have things changed for the brothers now that they're not as dependent upon each other anymore? The world may never know. (Or they'll tell us later on. We still need a Big Bad for this season, so it's anyone's guess, really.)



(Granted, a lot of this only makes sense if the writers knew they were separating the brothers that early on which I have my doubts towards honestly. Some of the later season seemed a little like cleanup to me.)



And that's my theory. Just putting it out there in case I'm right so I can say I told you so with impunity. ;)