40k is a small number. Tales of Vesperia moved about 20k units in Japan. There is a hope in the Sony fanboy methos that "everyone who wants Wii or 360 games must have already bought a 360 or a Wii, and thus new games only sell to the current base."
It's silly. Extra hardware is sold months in advance, at launch, and afterwards, for high profile games. Thousands of people bought PS3s just because of FFXIII. Does that mean the title is insignificant? No. People have already purchased PS3s just for that game. Just because there isn't a clear, immediate, and huge bounce in hardware, doesn't mean the game didn't help out the console, a lot. Just look at GTAIV, for instance.
As for my anecdotal opinion, all I can say is I'm very much interested in Fable 2, and if there was a way to play it for $199, but I didn't have a 360, well, I would possibly have to buy myself one for Xmas. Fable 2/Gears 2 combo are the only two games that I could see myself buying a console for at their current prices, that are yet unreleased.
Would I buy a $399 PS3 for LBP and R2? Prolly not.
Would I buy a $249 Wii for Symphonia and Shake it?...eh, maybe, but I'm a Tales fanboy
Would I buy a $199 360 for Gears 2, and Fable 2? That's the question this topic is asking, I guess. I think if people know about it, they will buy it. It's a sick deal. We've even seen hardcore Sony fanboys picking up the 360 lately, on this very site.