Yes and no. It has a government granted monopoly on relatively inexpensive but relatively fast letter delivery. I can certainly send a letter overnight by FedEx if I want to but it will cost a lot more and FedEx can't leave the envelope in the mailbox almost everyone has.

I do tend to think the USPS should be allowed to increase their rates to sustainable levels. Individuals are not nearly as dependent on being able to regularly send letters across the country for well under a dollar as they once were.