Because they're the only system sellers for the system this year? The Wii U has some great exclusives for it coming out for it this year, but those 2 are by far the most notable due to their potential to move units. I doubt X and Bayonetta 2 will be able to duplicate the effect.
Playstation = The Beast from the East
Sony + Nintendo = WIN! PS3 + PSV + PS4 + Wii U + 3DS