I think it has to do with not wanting to dilute the experience with split screen. Unfortunately, my wife and I would love to play a lot of games Co-Op but a lot of the good stuff is online only. I read somewhere that some company (maybe Sony) is working on TV technology that would work like the Parallax screen on the 3DS. Not to display separate images to each eye but separate images to two separate people. This would allow both players to play together on the couch while keeping the full screen experience. The game unit would have to do twice the work but game programmers will just have to take that into consideration. I think these TV's have a better chance to succeed than 3D because they can be used for other practical purposes besides gaming (like allowing two people to watch two shows on the same TV at the same time).