"Without ability to manufacture missiles, Iran would be unable coerce people to buy into it's Hormuz transit toll system, and the strait would reopen."

You don't need missiles to keep Hormuz closed. Cheap drones, naval mines and such are enough, and those don't require that much production capabilities, especially if you get some help from Russia. It's enough to hit a ship every now and then, which keeps the insurers away.

Even without any infrastructure IRGC could wage a guerrilla war for a long time.

In an industrial collapse scenario people in Iran, including IRGC, might have something more urgent than antagonizing ships. Things like subsistence farming.