I'd buy that if he was the lineal champ or holding all the important belts, but he's not. If the winner of Cotto/Canelo vacates and GGG wins it against whoever, and then STILL insists on staying at 160 to wait names out, then I'm with you. If he gets the Cotto/Canelo winner, wins, and then still stays at 160, I'm with you. But HBO can still do this hype job at 168.
And nearly everyone beating the "GGG must move up" drum is angling for him to fight Ward, which he won't do anyway, because he knows Ward is the truth and there's no $ in that L.