The problem is the world economies, including Iran, are so tightly connected together that such an attack would crash our economy on the first day and the rest of the world's economies the next day.
So even if by some miracle the U.S. does not countattack Iran, the rest of the world will.
Which country is more able to operate as a closed economy? Iran's is basically a planned economy with an authoritarian theocratic regime. They'll bounce back quick.