Want to explain how? I seriously can't see how the Eyetoy, even a more advanced one, would be used to control almost any standard game of today, not without other peripherals and a controller. Nor do I see the compelling interest in doing so. It's a fun little device where you can look goofy on the TV screen for a while, and scan your face to have it mapped onto a character. Camera control is an extremely gimped version of VR.
Yes, and it's already more successful than the Eyetoy. Thanks for making my point.
Nintendo has been in the gaming industry longer. We could take a look at Sony's non-gaming failures and gimmicks, if you want.
The Eyetoy has been out a year and relies SOLELY on mini-games. I would say what you can do with the touchscreen is already deeper than that, and it has a ton of potential when it comes to strategy games, RPGs, FPS and so forth. Advance Wars isn't a mini-game. Yoshi Touch & Go isn't a mini-game.
My one DS playing experience was at a kiosk that was running the Metroid Hunters demo, and didn't have a stylus. Wanna guess how I controlled it?
Funny that you mention the mouse, though. There are a lot of PC games that are controlled primarily with it! Can't say I know of too many that are controlled by webcam, though.

Despite the fact that a lot of PCs have cams.