Isn't this the same as with DMC4? I remember Capcom denying the possibility of it being ported to another console, and voilà, DMC4 is now available for PC, and 360 too.
I agree with Jyuu. I think that both, SE and Kojima do not want to promote any other console than the PS3, because their games are going to be released in that console. If they say that there is a possibility for their games to appear on other consoles, people would not buy a PS3; therefore, they would not sell enough titles when they release them.
Most likely, once they have sold some copies, they may think of porting those games to other platforms.