I agree with your assessment. I think the swiftness and ease of the Venezuelan raid gave false confidence of how easy Iran would be to conquer. I found the analysis, below, of what's going on in Iran a few days ago. It was written by someone I follow on social media:

Trump’s latest war moves are pretty brilliant. The guy definitely understands leverage—how to gain it, and how to exploit it.

This weekend Trump did two important things to gain and exploit leverage:

1. He threaten to destroy Iran’s oil distribution facility on Kharg island, through which 90% of its oil flows to the international community, if Iran continues attempts to shut down the Strait of Hormuz; and

2. He invited an international armada, including especially China, to join the US in policing the Strait of Hormuz and preventing attacks on it by Iran.

If the oil distribution system on Kharg Island is destroyed, nobody gets hurt worse than Iran, but China is a close second. By comparison, the US would hardly feel it, and even that small pain could be mitigated if Trump wanted by (a) implementing a US oil export ban, and (b) suspending the Jones Act. Those two acts alone would decouple US oil prices from international prices, and the US would have a glut of oil and gas at very low price while the rest of the world suffers.

So, Trump has put China (and Iran and Europe) in a double bind. Either China turns on its “ally”, Iran, and joins the US and the rest of the world in protecting shipping through the strait, or it declines to do so and risks having its oil flow disrupted for years to come. This move also calls Europe’s bluff. It can no longer pretend to oppose US action in the Middle East and instead must join or cede control over Iran’s oil and the strait exclusively to the US. And it puts Iran in an impossible position—attempt to close the Strait and lose effectively all oil revenue indefinitely, or decline to do so and lose its only remaining point of leverage over the international community.

Trump may ultimately decide to simply take and occupy Kharg Island instead of destroying its infrastructure. That move puts more US troops at some risk, but also ensures that oil continues to flow on terms the US dictates (including US dollar sales only). At that point the vast majority of the world’s oil supply would effectively be under US control—the US itself, Venezuela, Iran, and Saudi Arabia (which is loyal to Trump at this point) would all be more or less controlled by the US. And you can soon enough add Alberta, Canada’s oil to that list.

Friends, there’s no chance that China can successfully invade Taiwan under these conditions. None. And very little chance that it will even try.

Trump has China checkmated. Economically and militarily.

This person has, clearly, been indoctrinated into the mindset that Trump can do no wrong. There are several different reasons floating around about of why the US did invaded Iran—to prevent nuclear weapons development, for control of the oil, because Netanyahu wanted us to, to further enrich defense contractors, etc. Time will tell what the true reasons were but I think a lot of people just conjure and search for excuses/explanations to support their belief system. Most simply don't choose to (or can't) see the situation objectively. I think, as US citizens, we'll be lucky if we get out of this war without paying a heavy price. The longer it goes on the more risk there will be. Nevertheless, I really wish we could move beyond attempting to solve our differences in this way.