If economy was bad why DJ Stock market shoots up from 8300 to 13,400 in four years?

Around 8300 when Bush left office now it up about 13400 more than half. Isn't it Wall Street is the engine of economy? or it is just the casino for people to move money (gamble) around without any productivity backing. Or this is the way of rich people economy not for you and me normal folks. Rich people must love it whether Mitt or Obama be president.