could this have a positive effect for the introduction (technical, legal, societal) of autonomous trucks? I'd imagine that at least on the political side, there will be less pressure to protect soon-to-be-obsolete jobs when there are too few people wanting to do the work in the first place.

BTW, I don't buy the "we want to make highways safer, not cut the truck driver out of the equation" speak. If I just need personnel on site to handle on-/offloading and paperwork, maybe maneuvering into the loading bay, there is no justification to carry that personnel on the truck.