I’m not so sure the USPS is losing money on its Amazon deal. If you simply take their cost of doing business and divide it by the total number of units they deliver, it’s true that Amazon may pay less than this unit cost. But a lot of these USPS costs are fixed costs they’d be paying regardless of whether or not they delivers anything for Amazon. To examine this objectively you really need to look at just the incremental added cost of the Amazon deliveries, not the total cost for the USPS.
One of those incremental costs would be the cost of Sunday delivery which the PO started solely to satisfy Amazon.
The history keeps getting lost in discussions re: this issue. Amazon operated quite adequately prior to the PO contract, using a large variety of package delivery services. The only real down side was no Sunday delivery and the higher theft rates when packages are just left on the doorstep. Theft rates matter because Amazon routinely replaces stolen packages without charge. Going to the PO for last mile delivery cut part of the bill from the other services, who are still handling the leg between the fulfillment center and the local post office, and got them away from dependence on UPS/FedEx for the last mile.
What’s happened in the last six months is that Amazon has concluded it can do the last mile deliveries cheaper than the postal service, and has started doing its own home deliveries in many cities. I, for example, have only had one out of my last 20 purchases come by PO.
They’re going to have a balancing act there, though. Letter carriers have a key to locked buildings, Amazon guys don’t. Letter carriers also know the names of their customers, mitigating the problem of misaddressed packages. And if you move, they know where to find you while Amazon has to send a postcard to get the forwarding address. Nevertheless, having their own delivery service makes the newly announced one day delivery (order by noon, get it by 8) possible, so I think it’ll continue in the future.
I strongly suspect the PO last mile service will disappear in the next two years, or maybe just be reduced to rural routes.