360 is simply not popular there for many reasons as Starcraft says. I'm also not sure that the glut of JRPGs will help, nor that MS really think it will either.
MS made it clear recently they are no longer going to go crazy over Japan so it seems to me they are looking to try and secure Western JRPG players by paying for exclusives (as lets face it on native 360 install base in Japan plus the consoles core demographics it would struggle to get JRPG exclusives without paying for them) and if it helps in Japan then fine, and if it doesn't then stuff them they won't get the games then (or will have to wait for them to hit PS3 or Wii for timed exclusives).
As a result 360 has (given its current install base and core demographics) an artificially high percentage of JRPGs heading its way - hence 'king of JRPG' currently from a Western (but I suspect not Japanese) perspective.
Try to be reasonable... its easier than you think...
