Do you have any idea what the turnover rate is for long-haul tractor trailer drivers? The majority of new drivers move onto another career in less than a year.
Do you know what the average life expectancy is for a truck driver? 61 years. That's 16 years less than the US average.
Do you know what the turnover rate is? 91% of truck drivers work less than a year for a given company.
Do you know how many NEW drivers will be needed in the upcoming years? 1 MILLION new drivers need to be trained, to replace those retiring and of course replace all the new drivers who quit.
That last statistic alone proves you are incorrect in your assumption, as a million self-driving trucks could merely replace those who quit and not displace a single worker.
Sure, there are people who make it a life-long career, like my uncle who died in his 60s after driving a truck all his adult life. However at any given time a large percentage of the truck drivers on the road are brand new, which makes them more dangerous because they are inexperienced.
It is not a great career, but extremely necessary, so people are lured in with big signing bonuses (like $16k and they only have to stay for 6 months), to find the job really isn't great and not many people can really identify with it enough to stick with it long-term.
Regardless, we're talking LONG HAUL trucking here, not the more regional or last-mile type trucking that cannot be easily replaced by AI. There are many truck driving gigs that require unloading as well, which obviously a piece of software cannot do.
My prediction is the long haul depot-to-depot type trucking can be done totally self-driving, however I think we'll see something similar to the marine cargo vessel type setting, where a local maritime pilot boards the ship to safely navigate it in and out of port. I can see self-driving trucks arriving at a city, a truck driver hopping in, and driving it those last several miles to the destination, then back out, and constantly doing that kind of rotation as the self driving trucks come and go.