This makes me think that we'll end up with truck drivers who are more like tugboat captains. They know their distribution center and as automated trucks come in and park on the edge, they then do the fiddly work of getting it lined up at the right time to the right loading bay.

I disagree. That could be automated exactly like 'self-parking cars' which has been a feature in some luxury cars for a while now.

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.