No one said it was a big deal. It's just interesting that with all the talk about "omgz wii domination" that it isn't played as often as the Xbox 360. I have no idea why you quoted those numbers, they just prove the point even more. Now, at the end of 2008, there are even more Wiis out there, and they aren't being played any more than they were before. This could lead one to a few interesting hypotheses.
1) The Wii demographic is different.
2) The Wii has less lengthy games than the 360.
3) Wii owners purchase less games.
Those numbers are old. The 15.19 million number is from September 30th. That's from Nintendo's balance sheet, by the way.
http://www.nintendo.co.jp/ir/pdf/200...0e.pdf#page=11
They sold a shit load of Wiis in October, November and December. 800,000 in October and 2 million in November. Add that to the 15.19 total...and you have 18 million. And that's not including December, biggest holiday shopping season of the year.