People are really over-simplifying this issue down to who spent most on marketing etc. Products sell for a wide range of reasons, some are to do with marketing, yes, but a producer's relationship with distributors is also key. This determines how much shelf space is given to a certain console and its games, what the positioning of this shelf space is in the store, how much that item is pushed by promotional deals in store, and so on so forth. Microsoft clearly has done well in this regard this Holiday, in addition to some good U.S.-centric advertising.
At the end of the day, selling a product because of marketing, distributor relationships, or simply good content does not legitimise of illegitimise success in the market place. There is no such thing. There are only sales and lack of sales.
Claiming Microsoft only have gained success this Holiday because of their marketing prowess is applying the same kind of logic as the fools who said Wii was only successful because it was "a fad". There real question is why was the Wii "a fad" four years and why is the Xbox 360 "a fad" this Christmas? Through the hard-work and ingenuity of the people working in those companies to sell entertainment. Your normative assertions about what the legitimate means for achieving commercial success in the video games industry are nuts. There are only sales and a lack of sales. Nothing more.