Really? I thought they were split during Uncharted 3, to get The Last of Us started? I always assumed that after U3, they just put the team together again to focus on the new IP.
I have no doubt there will be a fourth.
I don't believe The Last of Us will matter, in terms of affecting the announcement/development of Uncharted 4.
I think Sony handing off Golden Abyss to a different team was a warning shot that they're willing to hand the reigns over to a different team to continue the franchise.
I think Naughty Dog has probably moved on. Usually, they do three and then move on, don't they? The Last of Us looks great, so...unless they want to wait until after that? Or if Sony even wants to wait for that?