Big time problems. I stopped sending things USPS a few months ago. Pretty much FedEx only at the moment. At one point USPS was by far the least expensive option for packages once they got to about 2 pounds or so. The difference today, for most of the things that I send, are minimal. Only bummer is that I have a daughter that lives in Europe - while USPS was slow, it usually got there and for WAAAY less than FedEx or USPS. Alas, we have had things go missing over the last six months going both directions. Not worth the hassle any more I am afraid.
Funny (or not) but USPS has been losing serious $$$ for years. When I was graduate business school, the USPS was a huge recruiter as they were going to solve the issues and become a profitable entity - that was in 1992! Ah well, not sure there is a solution other than continued subsidization. That has been the way for decades.