The better question is what's the probability of it coming out at all?
I kid, I kid.
On a more serious note, it's become apparent that there was some sort of exclusivity deal in place between Sony and Square Enix for Final Fantasy XIII, and Microsoft likely had to step in and pay Square Enix in some form to break that contract. The question remains whether there was also a contract in place for Final Fantasy Versus XIII, and whether Microsoft were willing to bargain for that game as well. Given the game has yet to be announced for 360, unlike XIII-2, I'm going to assume that there is a contract in place, and that Microsoft felt that landing only the "main" Final Fantasy XIII on their console was good enough for their purposes (even if Versus is looking to be equal as significant as XIII).
If it were simply a matter of making more money by making the game multiplatform, this thread wouldn't even exist, as such a decision would've been made long ago. It's obvious there are other factors involved.
