Their oil will never run out. Their is a common misperception that oil fields can "run dry". The reality is that the cost of extracting oil goes up as oil is removed. At some point, it becomes uneconomical to continue to exploit the field.
But, if the market price goes up, continued production become feasible.
The Arabs have the advantage that the costs of extraction are very low in many of their oil fields. OPEC is used to keep the price artifically high, giving them enormous profits.
They are constantly playing a balancing game of pricing oil to maximize their own income, while keeping it just low enough to prevent the US from developing alternative technologies.
At some price point, the US giant coal reserves become feasible as feedstock for alternative liquid fuels. Same with our shale oil deposits. But, the enviroweenies are doing their best to preserve the Western world's dependence on arab oil.
If we managed to shut up the environmentalists for 10 or 20 years it is likely that the US could produce liquid fuels at a reasonable price. Imagine a world where the US held both military power and exportable oil.