The postal service is a quasi government entity that has operated (not to get too deep into the politics of it) for many years at a loss. It does compete with Amazon, as well as being used by Amazon, but it's very different as a business than Amazon.

I got this when I told Gemini "post office loss retirement prepaid" because of other articles I have read that I cannot remember.

"In 2006, Congress passed the Postal Accountability and Enhancement Act (PAEA). This law forced the USPS to do something virtually no other government agency or private corporation has to do: prefund its retiree healthcare benefits 75 years into the future[0]. Essentially, they were legally required to fast-track billions of dollars into a fund to pay for the future retirement health benefits of current employees, and theoretically even future employees who hadn't been hired yet."

[0]: https://apwu.org/the-usps-fairness-act/