Iwata - Nintendo is always working on new hardware, and not all of it sees the light of day

“We do not think that Nintendo DS and Wii will last forever. Our internal hardware teams are always researching and working on new hardware so that we can launch them whenever we find a very interesting idea. You may not be able to believe this, but even when Nintendo has completed a hardware, it does not mean that we will surely launch it. [New] hardware is not needed until the time our software developers see the end in making new software with the existing hardware, or unless we have no more new market to explore and all the potential consumers have purchased our hardware. The more decisive factor is when the software developers will start demanding for new hardware as they cannot create any more software with surprise factors with the existing one. Nintendo has always been making the hardware in order to prepare for that day to come.” - Satoru Iwata

When will that day come for Nintendo when they have to do a brand-new portable or console? I think that’s at least a couple years off. Nintendo can definitely squeeze some more money out of the DS, and the Wii should be around even longer.

Link