I guess it’s luck to a degree, but I regard it more as calling Iran’s bluff. There is no defense for their overt funding and leadership of destabilizing terrorism in the region (as evidenced). They have been to war before, it’s not “luck” that they didn’t decide to commit suicide this time. They cannot afford war, and had they started, fighting a coalition of the US, Israel, Saudi Arabia, and a few others would not be good for them, even if Russia or China decided to float them for a while. It would have resulted in a horrible, horrible outcome for the people of Iran, and say what you want about the Theocracy but it’s not that dumb.