I just do not remember any of those exclusive games selling very well in Japan. Like I stated before, the amount of Japanese games that are only on Sony and Nintendo system in Japan is on a whole level compared to the Xbox. I cannot see any one in Japan purchasing an Xbox for Japanese content. If anything they would get the system for content that is not represented on the Sony or Nintendo system and it would need to be a different experience. Another RPG where there are tons of Japanese RPGs on Sony and Nintendo system I doubt will cut it. I will take a look at the data to see how well these games actually sold in Japan. Even so its not like the 360 was a top seller or even competitive.
Best easy example:
Star ocean the last hope,
Releases as a Time exclusive in Japan, Sells 166k first week , boost HW sales to 24K, rather impressive...
PS3 version comes out later, expectations were it will easily beat that number, it didn't....In fact it did way worse than expected. (Literally after a year of 'Sales are horrible the PS3 version will do so much)
Excuses that are brought up by fanboys: It was clear a lot of Japanese fans bought the game for xbox 360 or got an X360 in Japan for the game so you can not compare those games.
You can even find discussion about it from Vghchartz: https://www.vgchartz.com/article/7108/famitsu-japan-game-charts-and-sales-28-214/