Nintendo are certainly developing a next generation console at the moment and they are sure to be paying particular attention to the interfaces brought forward by Microsoft and Sony. So without paying any extra money for development or testing they get to see two alternative implementations being tested and brought to market. So instead of designing and releasing Wiimote 2.0 they can instead release Wiimote 2.5 when they finally release a next generation console.
Making an interface is harder than making a console which performs at a decent price. For performance there are many off the shelf solutions available and the pain has already been borne by developers and publishers to create an effective toolset for the creation of high definition assets. However the interface is another thing entirely and the onus on this is entirely on them to get right and to improve upon both the lessons of the Wii and the lessons learnt from Sony and Microsofts copy-cat attempts.
Do you know what its like to live on the far side of Uranus?