On the original topic, personally I think John W's idea is one reason
many people stay in Japan once they've been here a while (others might
include relative salary levels for comparable work, inertia, family,
friends), but is unlikely to explain why people would come here in the
first place.

Actually I feel like questioning the original premise. Certainly there
are some people interested in living in Japan for one reason or
another, but in truth, I've never noticed that there was any more
interest about this country than any other. As a tourist destination
Japan doesn't even rank in the top 25:

     http://www.infoplease.com/ipa/A0198352.html

(though Croatia and Ireland do), and while tourism and immigration are
different, it would be strange if the same people who longed to live in
a country had no interest in visiting there. So I suspect this is a
case of sample skew -- the perception of people lining up at the
Japan's immigration gate just isn't accurate, relative to other
countries. That's not to say that there aren't anime-obsessed people
out there who dream seriously of coming to Japan in search of
schoolgirls who transform into flying wombats, but in the scheme of
things, it's an insignificant number -- something that should allow
both schoolgirls and wombats to sleep better at night.

Personally I only came here because it was better than being shot at. I
thought I'd hate Japan. But that was a while back, and maybe they've
turned up the PR engine. No doubt the tax money is going somewhere...

M