Put it straight, how do you know "since most of xbox users gonna buy "ehem" copy..."? Don't be katak bawah tempurung, seeing people around you pirate doesn't mean the rest of the world do the same.

The best MGS still stays on Gamecube, not on any Playstation. But no harm done if it's release on 360, no matter how many discs there are (remember, the 28 or so GB are uncompressed). More people can enjoy a master piece (albeit a bit repetitive by now) if it's released on other platforms.