I remember hearing somewhere that FF13 was effectively done, but squenix didn't want to release it is because if they released it right now everyone with a PS3 would have to buy two copies for it to be profitable (Exaggeration). Now, I can't source that claim, but it makes sense, and shows the real reason that they are bringing the game to the 360 in english-speaking regions.
In all reality, it's not taking longer for Square-Enix to release FF games, they're just not releasing core games in the series. They're gonna release 3 games for final fantasy 13, new Crystal Chronicles games, not to mention the other Ivalice games and their cavalcade of remakes. Squenix can make more money on these games than they can making big budget main series titles. I mean, Revenant Wings sold over a million copies but probably cost less than a tenth as much to make as a main series game.
Wii has more 20 million sellers than PS3 has 5 million sellers.
Acolyte of Disruption
