Just because you don't send physical objects anymore does not mean everyone else does not.
That's a straw man. I send physical objects several times a year. When I do, I use UPS or FedEx because the Postal Service sucks at it. My expectation that the USPS will die does not mean package delivery has to die with it.
USPS's bread and butter has historically always been letters and bills. Nowadays that is rapidly drying up, so their bread and butter has become delivering advertisements to our houses. We don't really need to maintain a government funded agency for advertisement delivery.