The Iranian regime has a very high pain threshold, much higher than the US. They are willing to take a lot of destruction without giving in. Assassinating Ali Khamenei was a huge mistake. He was evil in a lot of ways, but he did care about his people and appeared to actually be against nuclear weapons. The new leaders care less about the people and are willing to let Iranians suffer tremendously.
The US didn’t seem to have a plan for the Strait of Hormuz. There were plans on the shelf, but no real reworked plan with preparation.
Opening the Strait of Hormuz by force would require ground troops, but Trump is against that.
Trump indicated verbally multiple times that he has a low pain threshold with regards to the economy. Why would Iran give in when Trump has indicated that he can’t take the pain?
The US didn’t fix its munitions shortage before choosing to attack.
The reporting indicates that Trump was for this war and most of the rest of his administration was against it.