"What do you think you will find in Japan ?"
- > please note that I am really not a Japan specialist, I may write total BS but this is my point of view anyway
Japan looks like the Ultimate challenge because of :
- Strong economy
- Hard langage
- Isolation (as an island)
- Social pressure
So if you succeed in living there, then you earn the jackpot !
Nowadays, the World is...well...getting crazy in many ways, meanwhile Japan looks stable/strong/happy. In a way, to live in there may seem "protective" for a lot of people. Moreover, the japanese animation/manga/media are fun and this is the place where you can benefit from the best technology on Earth, so why should I waste my time in France (e.g.) ?
Finally, some people willing to live in Japan might want to feel "unique". I mean an average Joe in London will be special in Tokyo, as he would look different
Once again, I'm not a specialist, I'm just replying with my gross feelings
