In the past Square Enix and other developers used to fight over the Japanese market, but that has changed. They now target the European and North American markets which far exceed the Japanese one, as Japanese games appeal to the Western regions more and more.
Square Enix used to translate their games and release them overseas after a couple of months, but that's about to change says Square Enix's president, Yoichi Wada: "We aim to make simultaneous releases a standard".
One example of the change we can see with The Last Remnant, which is Square Enix's first game that will have a simultaneous worldwide release. One can only hope Final Fantasy XIII will have a simultaneous release, too.