Xbox One has been lagging behind lately. Assuming it starts destroying PS4 every week, it can get about 3 million more sales this year (and crush the PS4 every week from now on). I say it gets to 9.5 million at most this year, assuming sales pick up in a big way. It is still a great system, but PS4 got them out of the gate and is probably going to be 20 million by summer of next year if not sooner.