I don't think i said it would stop selling. By 2012 (5 years into lifecycle) i think the Wii will have lost sales momentum and will need a "refresh". PS3 will eventually succeed as it will last longer than Wii as its clearly more future proof. Hence the need for Nintendo to think about how to get around this...
Nintendo loves its hardware updates too (GBA, GBA Micro, DS, DS Lite) and will clearly be in a position to provide a cheap and powerful update to the Wii without changing the control interface. Wii 2 or Wii "HD" (whatever they call it) will be a console to sit side by side the current console and will appeal to 2 different demographics, in my opinion (like PS3 and PS2).
I take your point that it may be longer than 2012 before they release the next console, i was going off previous console lifecycle history. Sony are the first to claim theirs will last 10 years, something i'm sure Nintendo are thinking about...
