He may just be saying shit at this point. He cannot believe he will finish the story and wants to have as many seeds out there so if someone else finishes it, their bases are covered saying it was all his plan from the start.
Also I remember reading all of these multiple times and my thought throughout was if anyone survives it all it was going to be Sansa.
Not because she was the most sinister or most coniving but because she was always going to be a pawn and would stab the last man/woman standing. It was going to be pure dumb luck she lived through it all.