The question really is what does 'winnable' mean. From a corporate stand point of view, gaining market share, along with year over year, and generation over generation growth, with PROFITABILITY is winning. Based on that, Nintendo is the clear winner. They have gained market share, and have huge profits. They can do nothing to loose this generation. Microsoft is also a winner. They have gained market share, they have become profitable, and clearly have become dominant players in software with microsoft game studios. The dominance in Noth America is clear, they have achieved Parity in Europe, and have improved in Japan, but perhaps not as much as they liked. Microsoft has also layed the groundworks for future generations with adapting the gaming console with a center of media. Live is in its infancy, and likely will be the dominant player for intyerface with other applications (ala netflicks, Twitter, facebook, instant streaming, etc).
Sony is the clear Loser. They have lost market share, they have lost billions in the gaming division, and will not recoupe those losses this or next generation. This setback financially will hurt them next generation as well as they will most certainly be behind the loop when the Wii HD comes out along with the next Xbox. Their arrogance has cost them dearly, as they have always been one to try to push their propriotary formats (example -Bmax, propriotary memory sticks, and of course blu-ray). If not for Toshiba's foresight in that HD physical media will be a niche product, and pulling out of HD-DVD (and Toshiba does have the resources to drag on a fight for years), Sony would be in an even worse finacial situation because of blu-ray. (They still may be because many people beleive that streaming HD will be the preferred format of the near future, not blu-ray).
My personal thought is that Nintendo holds all the power with regards to gaming consoles. Even if the Wii HD comes out in a coupel of years with similar specs as a PS3 (which I doubt as there would be no reason not to make it more powerful), It will continue to keep marketshare and continue to grow. Sony' s main competetor has alway been Nintendo, not Microsfoft. Wii-HD will likely put the final nail in the coffin for the PS3 as they will control Japan, MS will control America, and MS-Nintendo-Sony will split Europe.
And by they way, PS3 is not going to catch Xbox with regards to consoles sold. Already the numbers are reversing in NA with Xbox selling more, and will continue the rest of the holiday season, last year Xbox outsold PS3 > 2:1 holiday season in NA where the bulk of console sales are. I expect parity or PS3 to be higher only because of Japan sales, but with regards to software, the big multiplatform games are going sell and push hardware much more than 1st party games. CoD:MW2 will push more consoles than any other offering this year, and we all know that Shooters sell extremely well in NA..........







