From my perspective, there's little to be done. The casual crowd is pretty well shored up as Wii owners. This leaves only the HD gamer market available for the 360 and PS3. In the end, it comes down to trying to convince as much of the current userbase of those systems that motion controls are good for "core" games.
Between a cheaper Wii, and the brand name recognition, it'll be very difficult for Sony or MS to convince a casual /non-gamer that they should spend an extra $150+ (console difference + motion control systems) just for a similar gaming experience, especially with a lot of people continuing to hurt financially and (hopefully) recover at some point in 2010.
I still see the HD motion control offerings as a "test system" to see how much of their fanbase would adopt a system all based on motion controls next generation.
As for Nintendo, it's hard to say. We were all blindsided with the direction they went with the Wii. They are known for their innovation, so honestly, its a big question mark block.







