Perhaps this is why economists often talk in abstract terms. Greenspan dismissed the bad fall out of the 2000+ stock market crash pointing to the unusual rise as "irrational exuberance," and dismissed the housing bubble as "speculative price imbalances," and said "a national severe price distortion seems most unlikely."

But, in the U.S. one can see that rush to seek short term profits has trumped over building strong economic fundamentals. High borrowing ends up as consumer spending, mainly on foreign goods, and less on investment. Housing bubble was mainly due to unregulated lending by large financial firms, trading sliced and diced morgage-backed securites, disguised as complex financial instruments. Absent a technology/medical advance that can propel U.S.'s world leadership, U.S. economic dominance will be on an inexorable downward trend.