We are ingoring the fact that Lost Odyssey is a 360 exclusive, so the first question would be would it have sold better was it a multiplat.
We are also ignoring the fact Lost Odyssey may be a better RPG than FF XIII, but the latter is not really an rpg nor was it designed as one, its a mixture of rpg, action and tactics.
Thirdly we are still ingoring another fact that for the first time FF XIII tried to break from the classic jrpg story paterns and concentrate on the conflicts amongst the team itself. Many didn't like that but we have a game that was bold enough to to something different and one that was a total cliche.
A brand name alone doesn't sell you 6.5 mil, don't be stubborn people. Lost Odyssey is a very good game BUT it doesn't do any new tricks.
A game that deserved far more attention from producer Square Enix (developed by Cavia) is the stellar Nier. Trully excellent game and innovating but it was rushed, unpolished, filled with tech issues and imbalances.
