I think that post s4, the show was turned into Samnatural and it has continued on in that vein, exceptions being s9 and 10 when I honestly feel that Carver did put more effort into writing for JA/Dean than any other showrunner before or since. And then we got s11 which wascthe transition from Carver to Dabb(which I believe happened very early on) amd Dabb reinstated Samnatural with a vengeance and I fully believe that that's how he's always wanted to end it and how he, in fact(in my mind) will end it.
I have no hope left for anything better or more from him than simply another version of Swan Song, only this time Dabb will try to find a way to make Sam's sole BDH role, moment, and sacrifice stick, and yes, leave us with yet another attempt at the thought that, Samnatural should be the lasting legacy of this show-to which I will continue to say Blech! and Yuck!!
But luckily, after it's all said and done the Dabb years can also easily be erased from this fan's mind.
I can remember so little from them even now. 😉