A big mistake here was simply underestimating the scale of Iran.There is value in much of what you're saying in your post, even though I don't necessarily agree 100% with all of it. However, no one involved in planning or starting this attack, underestimated the size of Iran at all. All of that would have been covered by all briefings. The US admin and military knew all of this, and frankly has planned all of this.
The US has some of the most capable spy networks, knowledge, and military experience on the planet. And yes, even the current admin takes advantage of this.
So the real question is, what is the end goal? None of the noise we hear from mouthpieces is really it. I suspect that causing trillions in damage to Iran is likely simply it. A bloody nose. I'd be astonished if 1000s of exit strategies weren't deep planned, maybe a dozen best-outcomes planned, before a single plane bombed anything. The US knows how to exit this.
The US military, and daily briefings have all covered every aspect of what's been happening in the Ukraine war. They know. They've been studying it. They're not surprised by it. They 100% knew that Iran has been supplying drones to Russia in vast quantities.
What I strongly suspect is that Iran is being given a message. One it didn't listen to when it was bombed months ago. Don't help Russia. Don't align with China. Don't sell oil to China. And also?
Right now, all those drones made-in-Iran? All the munitions. All the missiles. All the tech they've been shipping Russia? It's ground to a complete halt. So whether or not Iran was stubbornly going to continue to export these things to Russia, it can't, as it needs them domestically now.
Russia is now cut off from that supply chain, because Iran needs it for itself.
If you look at what's happening, Russia has been forced to withdraw from the world stage as it is bled dry by the Ukraine war. It first pulled back from Syria, and it (Assad) fell. It pulled out of Cuba, out of Venezuela, all troops and aircraft and support. Russia has ceased to be a world power, it's literally done. It's become nothing but a regional power, incapable of projecting any power on the world stage.
The Ukraine war is serving its purpose. The West and the US are only supplying enough weaponry to keep Russia bleeding. Never enough weaponry for the Ukraine to win, never enough support, the US just trickles weaponry to them. The Ukraine just serves one purpose -- keep Russia fighting, keep it off the world stage, keep it bleeding all its power and might until it's a complete empty husk.
Yet as Russia has pulled back, China has attempted to moved to fill that vacuum. It's been buying oil from places like Venezuela, and Iran. It was extending soft power into Cuba. The US cannot tolerate this, and back to the start, I suspect that this is also a secondary message being given. A message to China. "Don't do this".
Cutting Russia and China off, each for different reasons, could be viewed as a good success for the US. My thoughts are -- what's next? What other thing does the US want to cut off from China, and Russia?
Because I suspect that's where things will pivot to.
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(One thought here is, about exit strategies, is that just walking away and leaving the straight Hormuz a mess, will literally force Western allies to police that straight with their navies. The US has been pulling back from policing shipping lanes world wide over the last 20 years, and unhappy with its allies for not taking up the slack, or what it deems a "fair share". With Hormuz, US allies will be forced to take up the slack, an interesting outcome. This too would be an immense success for the US.)