If I recall correctly, in Japan the $-Â¥ cost equivalent for the game was about $70. (could be off on that, though). At that point, I WOULD buy it... so it was comparatively cheaper in Japan, and I bet that had at least a little to do with the great sales.
As for people saying, "Suck it up, games everywhere else cost more!" Well, to me it's a matter of perspective, what I'm used to. If I'm used to games costing $70, I just deal with it. If I'm used to games costing $50, and one costs $90, NEARLY DOUBLE, I'm going to have to really think about that.