If it happens in Iran it'll happen everywhere within a few months... Time for shippers to step up to the plate.
There are some places where it seems ludicrous NOT to collect tolls. Most of them have actual infrastructure that requires ongoing maintenance and repairs — the Panama and Suez Canals, the Bosporus Strait and Dardanelles, etc. In all of these cases, it helps that both sides of the strait or canal is in the same country.