There are a lot of factors at play:
Internet commerce has grown faster than the delivery systems that support it.
COVID has accelerated the shift of retail from bricks & mortar stores to on-line purchasing and delivery by shipping.
Weather is always a factor and the weather event doesn't have to exist between the origin and destination of your package to affect your package.
Political turmoil certainly doesn't help.
And probably the strongest factor is that people are WORN DOWN.
You cannot put workers in masks and expect they will be as productive as before.
You cannot separate employees that need to interact in order to do their jobs and expect the same productively. Just getting people into a break room, bathroom or brief job site meeting is difficult.
You cannot expect parents to stay home and handle child care and/or education PLUS work the same schedule as before.
You cannot reduce your daily manpower by 20%-50% because of potential exposures to illness and expect the same productivity. And you simultaneously cannot hire 20%- 50% more people and pay most of them to stay home.