Except route the oil demand away from it.

Sure. Bits and pieces. But not enough to route all the oil, no relief on fertilizer or helium or natural gas, and still more expensive than just shipping through the Gulf (which is why they weren't doing it that way before the war). So they still are able to achieve their strategic goals, even if a few million barrels get diverted out of the Gulf trade.

Their strategy is that they can endure the pain for far longer than the U.S. and its allies can.

Sure is! I'd way rather have their economy than ours.

Yes, we have the advantage of having a much stronger economy. But they have the advantage of not particularly caring whether their citizens suffer at all, but our leadership has the disadvantage of having to be responsive to the electorate. It's hard for us to continue prosecuting an unpopular war, whereas they run an authoritarian dictatorship where control comes from the barrel of a gun, not the ballot box. Plus, this is happening to their country - these are existential stakes for the Iranian regime, and much more modest stakes for us - still significant, to be sure, just not as significant as it is for them.