It looks like shipments are going to mess up the Amazon predictions this month. I'd imagine that bricks and mortar retailers are going to see the most traffic going into Christmas so IF the PS4 still leads on Amazon by the end of the month then it's a certainty the PS4 has won, but I'd also say that IF the XB1 wins only by one or two places then it's likely the PS4 will still win.
The PS5 Exists.