The USPS loses a lot of money. Even ignoring the pension pre-funding issue, it's still cashflow negative. For a supposedly 'private' company that constantly requires bailing out by the US government. The USPS is just another industry that the internet has decimated and mostly replaced. First class mail has fallen so much that only package delivery and junk mail is keeping the USPS (kinda) alive.
One of the Postal Services problems is that senior management comes from USPS career employees whose loyalty is to the postal service employees - not the business itself or even its customers. The USPS needs new blood at the top and it needs to start acting like a for-profit business and less like a business that has been captured by its union.