...and active threat of military action to disrupt other oil supply routes like the Gulf of Aden - is not going to persist indefinitely.

I believe you are dead-wrong about that. I do agree that Iran will exploit this. They will start charging for safe passage. Probably a lot. And that price will be tacked-on to oil prices (at least from that region), which will make it's way to the pump. Short of taking out Iran entirely (not really feasible) it will be permanent. Why wouldn't it be? Iran has everything to gain by making it permanent.

There are rumblings that Oman is making a deal with Iran to split the booty. Two nations sharing the toll fees. They are likely to be high. There is no reason for them not to make it permanent. Means more revenue for them, which they will need as the oil fields run dry sometime in the future (which they will, though I can't forecast when).