ninja dog: who is Treasure screwing over? The Japanese gaming public really isn't any different from anywhere else: there's going to be some folks who'll go "sweet, I'll get an Xbox or I'll buy this when it comes out". Then there'll be others who go "eh, I'm not going to buy a damn console for one frickin' game", but those people will move on. Look at Cave--are people picketing them for releasing stuff only on 360? Are they demanding the staff commit seppuku for dev'ing for gaijin?
Sure the samurai concepts of honor and shame resonate as part of the culture, but ask native Japanese how it is today, in 2010, and they'll tell you it's diluted now and not nearly as prevalent as before.
BTW, I'm Japanese.
Treasure is a small dev, so they are going to be drawn to Microsoft because it is easier to get a game approved on XBLA compared to PSN.
Finally, all Japanese devs interested in making money are doing everything they can to broaden the appeal of their games, including catering to Western audiences. From Capcom to Sega to Bandai, they all just want to make money off games.
I'm bummed there aren't as many niche game choices on PSN, but I'm hopeful that'll change as the subscriber base in the West continues to expand.