[SgtHooper]

That’s because it’s unconstitutional for any entity other than the govey to operate the mail system. And they use the USPS because it is subsidized by us poor saps.

[Olog-hai]

I don’t see anything in the Constitution prohibiting entities other than the federal government from delivering mail, not even in the Postal Clause of Article 1 section 8. Of course, the SCOTUS legislated from the bench in the case of decisions like Ex parte Jackson (which determined that Congress had the power to decide what can or cannot be sent through the mail, among other sweeping powers), but that does not speak to the actual constitutionality thereof.