In the American streaming series "Bosch," the main character, a police detective named Harry Bosch, kills two bad guys in a plane who are trying to kill him. He then goes to the cockpit holding a pistol taken from one of the dead men. The pilot looks at him and says, "You kill me, you kill yourself." Bosch says, "I'm a f--king cop, asshole." The plane lands safely and the pilot is taken into custody.
In this analogy, President Trump is Harry Bosch; the pilot is the Supreme Leader of Iran, Mojtaba Khamenei; and the plane is the world economy. Khamenei can crash the plane, that is, kill the world economy by destroying the oil and gas infrastructure throughout the Persian Gulf so that it would take years to rebuild. Khamenei could go even further and destroy desalination plants in the following countries with noted dependencies on such plants for drinking water: Saudi Arabia (70%), Oman (86%), United Arab Emirates (42%), and Kuwait (90%). Doing this would make these countries largely uninhabitable. It's important to recognize that the Iranian military has demonstrated that it can hit precisely what it wants to hit with missiles and drones and destroy it.
Sticking with the Bosch analogy, it's still possible for Trump to let the plane land and save the world economy from complete destruction. The difference is that the pilot—in this analogy, Iran in the person of its Supreme Leader—must be allowed to go free and live undisturbed. That is what Trump believes he cannot allow because it would be a humiliating loss.