That's not even as hard on the body as other physical jobs. It is not a well regarded and the community of peers you interact with means that it isn't a very desirable job.
The reason we lack truck drivers is because of pay, it costs a lot of money to get people to forgo a family, or a home, or sleeping in their own bed, waiting around in the middle of nowhere not getting paid just waiting, plus the costs of road food, the cost of maintaining and insuring your own truck, ect.
It's also a pretty shit job.
https://www.bls.gov/ooh/transportation-and-material-moving/m...
There also is not a truck driver shortage
https://www.businessinsider.com/truck-driver-shortage-not-re...
Also everything I have heard from truck drivers makes it sound not so great at all. They are under constant pressure to keep driving even while tired and are constantly gps tracked for performance metrics.
I remember visiting the Daily News (a NYC local newspaper) in the early 2000s and on the tour learned that the unionized delivery guys could make six figures. That was almost 20 years ago. The fact that the same salary as 20 years ago is still possible doesn't really say much.