Also, middle class of the US has been shrinking because:
1) higher percentage of wealth consistently turns to wall street and
2) revolutionary technology has caused less and less work force necessary.
Absolutely agree! Comparing to my colleagues who don't play stock market, my few years experiences with stock market gave me some edges. those edges may help me to prevent my 401k shrink 50% right before retirement if 2008 were to repeat all over again at that time.