I agree with most of what you wrote other than the first sentence. Iran is weak right now, relative to the past. That is probably why the war is happening now as opposed to in the past.

Nonetheless, Trump has been utterly incompetent on the political side of things. There is low support for the war in USA, which directly translates to being risk averse when it comes to casualities (or even short term oil prices!). Trump is happy to bomb iran from planes. He does not seem willing to put american soldiers at risk in a significant way or be in it for the long haul. I'm pretty sure Iran has noticed this and it informs their strategy.