It's primarily because 220 of said 380 games are on very poorly-performing consoles in Japan - the X360 and PS3.
Since neither console has an amazing userbase, it's kind of hard to sell games when no one owns the system.
Go look at the DS - it's selling games hand over fist, and it's a HANDHELD for crying out loud. It has the user base, and the users are certainly lapping up everything that's made available.
Back from the dead, I'm afraid.







