Maybe it's just me, but if the oil rich countries (Middle-East) are so rich, then at $40.00 a barrell, why don't they just shut the tap off.

People, Companies and Countries have to balance income and expenditures. Expenditures are planned based on an expected level of income. When people lose their $40/hr job, and have to make do with a $10/hr job, the expenditures that were possible at $40/hr may not be possible at $10/hr.

Middle East countries are in a similar situation. The countries budgets (social programs, vast infrastructure changes, construction, etc, etc) have been prepared based on the belief that they could receive a certain amount per barrel of oil. Some countries require a price of $60 per barrel, or their economie are in trouble.

They are not so rich that they are in a position to turn off the tap, they need the money.