Lol BnM, I think it's possible for Wii2 to launch in March 2012 so the shoe eating is only for Jan - Dec 2011.
I get the momentum argument, but I (and apparently Iwata and Reggie) think the Wiis momentum can continue for a few more years especially through 2011.
You posted somewhere about how important the holiday season is to Nintendo. Even if this holiday season is abysmal for them (which is highly unlikely) they would probably need two bad holiday seasons to be convinced the Wii ride is over, and with Zelda and 3DS still to come I can't see how the 2011 holiday wouldn't be a good one for Nintendo.
I know Nintendo hasn't said anything about but they HAVE to be looking at some kind of 3DS/Wii integration, like using the 3DS as a controller that displays extra content in 3D or being able to use some of the new weapons/swords/tunics in Skyward Swords in OoT 3D or some similar type of game interactions. If the 3DS is half as popular as the DS any interaction between it and the Wii will boost Wii sales if even slightly, and with how well it's selling Nintendo might only need slight boost to wait until 2013 to launch the Wii2. I'm hoping it's 2012 but 2013 is possible if their 3rd party support gets a big boost which will be evidenced or dismissed at E3 2011. Even if dismissed, the Wii has enough momentum to carry it through 2011 which is only a month away and only lasts for 12, a pretty short time in the console world. Not so much in the smartphone world, because, as you said, the multiple sources of competition demand quick shifts. But Sony and MS are in no position to release new consoles that are significant improvements over their current offerings, they can only offer peripherals and small upgrades, which Nintendo is also capable of doing.