It is not really producing wealth if the derivatives per barrel of oil exceeds many times the value of the barrel of oil ... when it was at its high price.
More vapor ‘wealth’ was created than actual wealth form profits.
Precisely why it is failing, it is no longer real wealth, and because it is(was) one of the few sectors of the economy that was (up until recently) active we are seeing a strong down turn in the percentage of middle class (long term) and GDP (short term). Look for thing to get worse, for all American’s until, policies change to promote the creation of real wealth.