I'd emphasize Amazon shipping and last mile delivery is clearly anti-competitive "dumping" practice. Provides a moat against potential retail competition and is very much akin to Standard Oil controlling the rail roads to ship oil on. There is a reason why the USPS and neutral third party private shippers like UPS and FedEx should exist: to provide an universal infrastructure for mail order retailers, such as Amazon outside of AWS is. Amazon shipping and Prime are certainly not profit centers for the company but loss making dumping endeavours that provide an anti-competitive moat. It is neither realistic or socially desirable to expect every mail order retailer to roll its own last mile delivery so the inevitable intention of Amazon shipping to customer doors with its monopsony "DSPs" is market power and anti-competitive dominance not customer service or fair competition.