Even if Sony put some hard money behind the Vita and created console selling games they still live under the philosophy that 3rd party games are the main reason behind buying their devices. With Nintendo owning the handheld world since the Gameboy it's pretty hard to convince anyone outside of studios who want to release uber Japanese games to spend capital on Vita development.
That's what's so dangerous about the Wii U, attaching the 3DS and adding another level of immersion. Long story short, it's not even a fair fight; Sony thought that their totally awesome 50cal rifle was perfect to take out Nintendo in a fight but the moment they stepped into the ring Nintendo was on board a zumwalt class destroyer 50 miles away laughing while ordering a bombardment of the area.







