One missed truck causes huge delays add a couple a whole store would be shutdown. The difference from driver to driver is huge. They can’t really just be switched like legos, each industry has its own trade techniques to understand.

Think fueling a tanker wrong, driving it wrong compared to overnight driver for driving for hours, or delivering in a busy downtown city. Each job has its own pool of drivers and some are so desperate the companies are training themselves and offering bonuses. They still can’t keep drivers, and driving just isn’t for some people.