Why the US Navy won't open Hormuz

I would not say the Navy can absolutely secure the Strait; I would say they can maybe secure it, and even then I would remain somewhat skeptical. I think it's hard to have a properly calibrated notion of the capabilities of the US military. It's very large and very well-funded, especially compared to other militaries, but its resources are not infinite. There are, therefore, necessarily things the US cannot do, even if we presume it better equipped than any other country. Our failure in Afghanistan serves as an an obvious, recent example.

Assuming you haven't read it yet, I would recommend this piece I submitted a few days ago. I'll quote the relevant passage:

For the United States, a purely military solution is notionally possible: you could invade. But as noted, Iran is very, very big and has a large population, so a full-scale invasion would be an enormous undertaking, larger than any US military operation since the Second World War. Needless to say, the political will for this does not exist. But a ‘targeted’ ground operation against Iran’s ability to interdict the strait is also hard to concieve. Since Iran could launch underwater drones or one-way aerial attack drones from anywhere along the northern shore the United States would have to occupy many thousands of square miles to prevent this and of course then the ground troops doing that occupying would simply become the target for drones, mortars, artillery, IEDs and so on instead.

One can never know how well prepared an enemy is for something, but assuming the Iranians are even a little bit prepared for ground operations, any American force deployed on Iranian soil would end up eating Shahed and FPV drones – the sort we’ve seen in Ukraine – all day, every day.

Meanwhile escort operations in the strait itself are also deeply unpromising. For one, it would require many more ships, because the normal traffic through the strait is so large and because escorts would be required throughout the entire Gulf (unlike the Red Sea crisis, where the ‘zone’ of Houthi attacks was contained to only the southern part of the Red Sea). But the other problem is that Iran possesses modern anti-ship missiles (AShMs) in significant quantity and American escort ships (almost certainly Arleigh Burke-class destroyers) would be vulnerable escorting slow tankers in the constrained waters of the strait.

It isn’t even hard to imagine what the attack would look like: essentially a larger, more complex version of the attack that sunk the Moskva, to account for the Arleigh Burke’s better air defense. Iran would pick their moment (probably not the first transit) and try to distract the Burke, perhaps with a volley of cheap Shahed-type drones against a natural gas tanker, before attempting to ambush the Burke with a volley of AShMs, probably from the opposite direction. The aim would be to create just enough confusion that one AShM slipped through, which is all it might take to leave a $2.2bn destroyer with three hundred American service members on board disabled and vulnerable in the strait. Throw in speed-boats, underwater drones, naval mines, fishing boats pretending to be threats and so on to maximize confusion and the odds that one of perhaps half a dozen AShMs slips through.

And if I can reason this out, Iran – which has been planning for this exact thing for forty years certainly can. Which is why the navy is not eager to run escort.

I'm not entirely sure of that anymore. The paradigm of war shifted that the US isn't yet equipped to handle.

Countering drone warfare has proven to be incredibly difficult. Risking your multibillion dollar ships to fire from a drone workshopped in an alley is just a bad value proposition whichever way you slice it.