If Iran tried to shut down the Straits of Hormuz, it's more likely that the straits would remain open for non-Iranian oil. With the loss of their oil exports, Iran would find its remaining military forces being hunted down and destroyed day after day. Not only would Iranian oil exports be halted, but so would imports. Iran depends on imports of food (over 100,000 tons a week) and gasoline to keep its economy operating.
It is more likely that trying to close the Strait of Hormuz would just be a suicide pact. sure, oil prices will spike, but even our West European allies will hasten to join us in the Persian Gulf to protect non-Iranian oil-exports. Aside from some type of war premium and extra insurance, prices will settle down again at a higher but livable level.
As with much else, Iran counts on us being too frightened to deal effectively and decisively with these nuts until it is too late to stop them at a reasonable price.
