This subject is very interesting to me. If I understand correctly, if I mail you more than you send me (us being countries), I thus collect more money on stampi

This subject is very interesting to me. If I understand correctly, if I mail you more than you send me (us being countries), I thus collect more money on stamping. We balance it by me paying you terminal dues (rated against my local costs). By lowering my shipping costs internally, I can also lower my terminal dues -- if it is within my control -- to you and thus also improve my exports. This is potentially a double negative for you, 1. if you labor or other costs are higher, you lose more, 2. your carriers try to make up for it by increasing your outbound shipping costs, affecting your exports Instead of doing real-cost rebalancing, the "fairness" balancing, is susceptible to be pulled down to zero and runs the risk of a disconnection with labor, energy and environnement costs. Further, this type of market mechanism favors a runaway dynamic ie. if a country ships a lot, it gets even better and better for them, as they develop economies of scale. Sounds like whatever made the multi-stamp system too complicated before 1969 might now be feasible with technology, as it may have been the more market-true, and thus future-proof approach.