All of the shipping companies have been buried for the last 10-11 months. Add holiday shopping, lack of qualified/competent drivers, and saturated networks and this is what you get.
If a local sorting facility is designed to process 25,000 packages a day, but the inbound volume is 30,000 every day, there are going to be problems. If there are only enough trailers and linehaul power to move 300,000 packages from a regional hub, but the sorted volume is over 400,000, there are going to be problems. If you need a workforce of 100 on road resources to cover 12,000 stops in a geographic area, and you have 15,000 stops and only 105 on road resources, you're going to have problems. If you need 100 vehicles with at least 300 cubic feet of usable capacity, but you can only source 90 vehicles (because every other delivery company is looking for the same vehicles), you're going to have problems. When there aren't enough qualified applicants to fill the open positions and you're forced to settle on lower-quality resources, you're going to have problems.
Now combine all of those complications into one scenario, for 11 consecutive months on top of the already significant predicted e-commerce growth. Add that up and you have 2020 through the eyes of the transportation industry. All this year has done, is bring out the weaknesses that were already present in the delivery/transportation industry. The USPS underperformed when things were good, why would anyone expect them to be successful under more difficult circumstances?
The solution? plan ahead, buy local, and be patient.