I'm not ignoring that it changes over time. The principle that 'nations pay for local delivery for free' as a matter of convenience, was established 150 years

I'm not ignoring that it changes over time. The principle that 'nations pay for local delivery for free' as a matter of convenience, was established 150 years ago. That basic principle remains today. If that agreement were not made an eternity ago, nobody would even think to suggest it today - because it doesn't make sense. You are missing the point when you're referring to 'making or losing money' on the deal. It's not so much about the cost of regular shipping - it's about the subsidisation of entire competitive industries. The rise of e-Commerce has changed everything related to shipping, quite fundamentally. A US subsidy on their own imports to China, even a smaller one, can make quite a substantial change in commercial trends. The treaty was not designed to do that, nobody was thinking in those terms, at that scale. Not even 25 years ago did we think individuals were going to be buying little parcels from China on an individual basis. The treaty now has to live in the context of e-Commerce and it should essentially be abolished for packages, because it simply does not make sense. In an era before computers, it might have made sense to honour each others letters. But now there's no reason why the sender just can't pay appropriate rates for shipping. Edit: I should add - there isn't a single argument presented by anyone on the entire thread as to why one nation would arbitrarily deliver another nations physical packages 'for free' or on reciprocal basis. This is because there is no reason to support it in 2020. It exists for historical reasons, bureaucratic and political momentum.