The PS4 is struggling to have decent legs at its current price point, and soon the PS3 will overtake it launch aligned. In addition, the PS4 will have its legs cut when the PS5 releases much like the PS3 did. Generally the January- March period is important for PS sales and it is already down 240k YoY. A price promotion in Feb/ March plus FF7 would have been great, but FF7 was delayed.
The only way for ps4 to reach 10 million is if it has a permanent price drop which im sure it will. Eventually they can still make a profit selling it for $200. History says PlayStation system will have a price drop the year its successor launches or right after