I think it goes to show that the market for consoles has become more conservative. When you compare the PS4, XBone and the WII U(yes the Wii U is a part of the market), the PS4 is probably the most simple in its configuration. It doesn't have extraneous gimmicks like a Kinect camera or Wii U tablet that increase the cost of the system. Sure the controller has a LED and a touchpad,but it's not a huge new way of gaming that leads to more casually focused games.With the PS4, you only really get a box and a controller.

The casual market that Microsoft and Nintendo built their machine to appeal to is already satisfied with their phones and tablets for their day to day fix. And for the majority of gamer in the market for a PS4 or XBone, they also have phones and tablets with a great selection of casual games. So when the choice is given between the different consoles, they choose the one with a more enthusiast focus. Their itch for casual games is already sated. And it doesn't hurt that the PS4 GPU is 30-50% more capable and at the same price as an XBone(Kinect-less SKU).