More specifically, letter volume has been going down and parcel volume has been going up. Basically, there's been a huge shift in what the US Postal Service act

More specifically, letter volume has been going down and parcel volume has been going up. Basically, there's been a huge shift in what the US Postal Service actually does, and their ability to cope with it has not been helped by - for example - the media creating partisan conspiracy theories about reducing the number of sorting machines that can physically only sort letters to rebalance their infrastructure being an evil right-wing conspiracy to destroy the postal service.