I personally get a massive benefit from USPS being cheap, despite the fact that I send no mail. It provides a massive low-cost physical delivery network across the country, with service to every address. This is a benefit to me because it makes business and personal communication simple and reliable. If I need it personally, it's there. If I don't, I still rely on thousands of parties who do.
Your position is like claiming the interstate system is useless because you don't have a car, ignoring how all those goods your life relies on actually get to you.
Maybe you're an autodidact like many other engineers, and maybe you would have done better without schooling. Such people are a minority.
Like many, I think you're confusing "the school system is flawed" (it is) with "school bad."
If the schools in a given country were pumping out geniuses year after year then maybe you would have a point.
Poor community? Sorry Timmy, your schools SUCK.
Rural community? Get to farming Timmy. You dont deserve a GOOD education either.
Living in a rich suburb of a big city? Congrats, your schools are well funded and low student:teacher count. Your education will actually be pretty damned good.
The unintended consequence of this is all the junk mail that makes regular mail a horrible experience to interact with.
Raise the prices , remove the spam.
When things cost as close as possible to their MARGINAL cost. The marginal cost of mailing a letter is very low, almost certainly closer to $0 than $0.83, especially if you accept letter carriers have to run their route every day regardless.
The problem of course is the USPS has enormous fixed costs, including I would argue the pensions (honestly not sure how they would be accounted for in a GAAP sense, I'm absolutely not an accountant)
Federal funding has long distinguished between the two for other things like transit. You're only allowed to use federal funds for capital expenses, not operational expenses. USPS getting a taxpayer subsidy for their fixed costs doesn't seem that nuts.
but that "value of being cheap" is provided to the people using the mail (or other delivery services) for that transaction; it does not benefit people who are not involved in the transaction but have to pay the subsidy. The economy operates most efficiently when things cost what they should or as close as possible.
what Microeconomics is about is calculating what is cost efficient and what is not; free mail services are not; less free mail services are not; rationally priced mail services are.