Wii has dominated sales for each month since it's release with the exception of September 2007, where the 360 outsold it (this is not counting handhelds, but the DS is the only one that beats either of them anyway).
Also, look at the original numbers compared. 17 million > 13 million, but at the same time the statistics for the 360 are from 4 days ago while the statistics for the Wii are from September! Not only are you leaving out a little over 3 months of Wii sales, but that is the holiday rush and a large increase in Wii sales that was totally overlooked. The Wii is nearing 20 million units sold, and has been around for a year less than the 360 has, meaning it's sales are generally over twice as high.
As far as how well the 360 has sold, the PS3 has had comparable sales throughout it's lifetime. It didn't sell extremely well, but has picked up over the last year.
Isn't it safe to say that the majority of Halo 2 owners got Halo 3 as soon as possible? While the game sold extremely well, it has obviously not maintained that level of sales. It sold over 4 million it's first week, and in over 3 months, only sold 4 million more. Sales will probably continue to increase faster than that of an average game (eg most games that are not Halo). Brawl will not beat those first week sales (although I have read and heard numerous accounts of Brawl having more preorders and interest in specific, but not all, retailers).
There is also the fact people really devalue Brawl's hype. For the amount of advertising the game gets, it's incredibly hyped. Everyone I know who has even the slightest interest console gaming, save for a few people who "fear" the Wii's controller (they are just afraid to try it and won't even play the console) is interested in Brawl. Comparatively, most of them don't care much about Halo, although quite a few of them got it (and the only person who has said much about it says he thinks Halo 1 and 2 were better xD).
There is a lot more hype than people think, especially for a game which relies so much on "word of mouth" advertising. Halo had Mountain Dew bottles and billboards, Brawl has one site and tons of fans. It's doing pretty darn well in my opinion.