Only USPS ships everywhere. If you go to UPS/FedEx/DHL, they will tell you they ship everywhere and take your package, but if they deem your package not profitable enough they will hand it over to USPS.
The shipping market is incredibly complex with USPS and FedEx actually being each other's largest customers.
That is true, but it is also true that UPS and FedEx still operate a lot of non-profitable areas. They rely on easier metro areas to help subsidize the losses.
The shipping market is incredibly complex with USPS and FedEx actually being each other's largest customers.