Epic statement!
Why would they take a game engine designed around the strengths of the Xbox 360 and try to shoe-horn it into the PS3? It would probably take a great deal of effort to make a game which was designed with the Xbox 360 in mind and then tuned even more so with the second iteration work on the PS3?
They are a private company and they do whatever they feel like doing, much like Valve in this case. If they only want to make exclusives they have no share-holders to please but themselves!
Do you know what its like to live on the far side of Uranus?