If you think the only role of a truck driver is to steer and press the pedals you are terribly mistaken. That is the easy part to automate.
however many truck drivers usually are tasked with loading and unloading their trailers, most likely to occur when flat beds are picking up special cargo. Movers also tend to be part of the work crew as well. More than one friend has ventured in trucking only to return when they realized the amount of hard labor, if not dangerous labor they faced.
The most challenging part mentally is accurate trip planning. Drivers try to predict exactly when to move to ensure an on-time delivery and have too many variables to do this with high accuracy. Then they will typically falsify logs and run illegally to make the logs match the date and time stamped documentation (toll reciepts, times stamped on delivery reciepts, etc).
I think that you'll find large trucking companies are happy to keep using cheap expendable labor, who will willingly bend the rules, as this gives the companies the plausible deniability they want.