[samurai007]

Let me add something else... why do most people want to go to or live in Japan? The reasons vary from "I want to travel around the country and experience the culture" to "I want to buy tons of manga", and everything in between. The thing is, most of those reasons have finite limits, or at least diminishing returns. After you've traveled from 1 end of the country to the other, and visited more castles, temples, and interesting sites than you could count, the desire to see yet another one is far less than it was to see your first 1, 2, or even 10 places. And buying manga can be fun, but what happens when you already have 1500 manga? Is there still as great a desire to buy number 1501? No.

"Experience Japanese life and culture" is a common reason for going, but how long do you really want to experience it? For many people, 2 or 3 years of living there is enough to satisfy that desire, and then other desires begin gaining in relative importance. "See my family again" or even something like "get good Mexican food or southern-style BBQ ribs", may become more important after several years away than "spend a 731st day experiencing Japanese culture". Desires like that, which are relatively easily fulfilled back home and have never been very important, can surpass "living in Japan" once living in Japan has become the everyday norm and seeing your family or eating a food you miss is an incredibly rare treat, something that you can only do once a year or less.