You make the mistake of correlating wealth with the intelligence of the average person. The average person did not build the businesses that made America. And capital is a powerful tool, properly managed it grows exponentially.

By the way the average Chinese person is starter than the average American. Intelligence is not the same as education. Nor does having running water make you any smarter than someone who does not.

IQ's by nation. http://www.sq.4mg.com/NationIQ.htm