I suppose Nintendo wants to push folks to the WiiU.
My family still uses the Wii and I'd even pay a modest fee just to keep the servers going...but, clearly, Nintendo knows that even if many millions of folks were willing to do this (pay to keep old hardware and games relevant), it effectively delays migration to WiiU.
Wii = Windows XP, the older uncle who refuses to die. (I still have XP on my desktop, by the way). Personally, I don't want the old bastard to die.