I'm looking for all these Xbox gamers that care. Anyone that cares about Final Fantasy games highly likely has a Playstation. Outside of 13 and 15 that franchise has deeply been associated with Playstation for a long time. If Final Fantasy games actually sold meaningful quantities on Xbox it wouldn't be an exclusive. You don't see games like Assassin's Creed and Grand Theft Auto as Playstation exclusives because they sell so much elsewhere nobody is tempted to ignore those other audiences.
People who care about JRPGs might own an Xbox but they also own something else that actually gets them.