Because they were the exact same thing as the ohter guys, just worse minus the first party titles. The Wii is not a great piece of hardware, niether the graphics OR the original motion controls (before wii plus). It's a crappy machine, but it isn't what is out there already.
If you are going to do what the rest of the market is doing, you better be top notch. If you're not doing what the rest of the market is, you can save yourself the financial trouble of being top notch. Right now everyone is trying to get down with the whole motion control scheme.
If that is what the next home console generation is all about, then you can expect to see Nintendo lose if they try to repeat another gamecube. They'll fail since the other guys can outspend on motion technology.
