I ... Don't believe you are correct here. The US has the most destructive military (non-nuclear) on the planet. The country simply does not have the appetite to actually commit blood, sweat, and money to this war. If they start striking the US, the US people will see it as an existential threat and be far more willing to dedicate as many resources as nessesary to eliminating the threat regardless of the fact that the US started it. That would be bad for everyone, but especially Iran.

It is far better to have the US population largely split in their support for the war effort.

If Iran leveled the pentagon and nothing else I think the average american would support Iran more.

In the US war on Vietnam, the anti war stance of the US population of draft age had a significant effect.

Missiles and drones can only fly so far before they run out of fuel. The US is half-way across the world from Iran.