They can’t set their own rates and have an obligation to deliver everything, which leads to them shipping many things (not just Amazon) for free. There is no other country in the world, no other private business that lets you send first class letters for $0.60 for a reason. For years they were also wrangled into a treaty obligation that forced them to ship small packages from China for a loss.

They also have huge retirement —prefunding obligations which is pretty much unprecedented in either private business or government agencies.

All of these public obligations are poorly thought out and largely out of the control of the USPS itself. People bitch about USPS being inefficiently run and that’s true to some extent, but the most fundamental issues they struggle with revolve around factors beyond the control of USPS management.