Clearly, you've not been around for much discussion around here.
This is going to be next summer, and they DO need to motivate greater sales eventually. By that time, they'll be into much higher levels of production, and the Wii won't have the luster that it's been enjoying so far to casual gamers. Additionally, the cost of the technology will be much, much cheaper by then. It's already dropped considerably. At launch, the Wii was making Nintendo $47 per console sold. Imagine what it's making now. Come the summer slow-season, much fewer people will be getting motivated to buy a Wii. Drop the price and add more goodies, and you'll motivate all sorts of people to spend money when they normally wouldn't be. With the dropped cost of the technology, I'll wager that they'll still be making about $55-60 per console sold at that price.
Meanwhile, the technology in the PS3 and the 360 is also dropping in cost. Considering that Sony and Microsoft both have been combating who can drop their console's price more, I expect there will be another price drop for both of them for the summer drought season. This will put both of them into threatening distance with the Wii, putting them into mass-market affordability, and Nintendo has to address that. Since they'll still be able to afford all sorts of neat changes to their SKU (with cheaper techs), it'd make logical sense for them to drop their price a few bucks and throw in some better tech.
Remember the DS? Nintendo released the enormously better DS Lite (which was more expensive to manufacture) and dropped the price. And it began selling like hotcakes. Granted, they were doing that for slightly different reasons, but it still had to do with competition moving in on their grounds. Moving through next year, there will be no more hardware shortages unless Nintendo motivates people to buy more. Production will likely move up to 2.5m per month at least. Gotta do something to increase demand.
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