The Japanese suffered from the mother of all bubbles. The Nikkei increased 400% from '84 to '89. When it popped, investors pulled their money out of the country. Not long after, the USSR went under, the US began its bull run and China decided to knock a few bricks out of the Great Wall. Apparently, investors found better opportunities outside of Japan. If the Nikkei consistently moves up as the S&P moves down, we know the wealth is flowing back into Japan and we have a long road ahead of us, but like other posters said, the U.S. and Japan have different economic systems. I wouldn't wager against the U.S.
\ Very good point, especially about their immigration. Japan is the country of old people and they are getting older. Their immigration policies are racist and only immigrants who are wellcomed are other japanese from other parts of the world. If they don't change this soon, they are heading down.