Why do you think Nintendo will cut the price just because the competition does? You may have noticed all the other price cuts they've had without the Wii getting one. Sounds like thinking from two years ago, to be honest.
It's not news that they're working on Wii's successor. No big company ever stops designing new products - you can bet that each of the big three have been working on their next consoles since the current ones launched. Plans for them change often, but preliminary work would have started very shortly after Wii, PS3, and 360 launched, respectively.







