They make up for it in volume
Love that joke.
Oil does not come free from the ground. Drilling & fracking cost money. There is a price point for many drillers where there is no profit in drilling, so they don’t drill.
Saudi Arabia is trying to drive the US drillers out of business & they are having some success at this. These low, low prices are not good for the US in the long run. Iran’s return to the legal market will not help either.
Happily, the terrorists are mostly dependent, directly or indirectly, on oil profits in the ME which are down substantially.