Someone still needs to accompany the truck. Sure perhaps in the distant future this is not true but at least for the generation of current truckers a person will still be necessary.

Yes wages are the biggest expense but I think the big pushed for self-driving trucks is 1) Reduced liability 2) Trucks can be operating nearly 24hrs a day. 3) Greater fuel efficiency.

So sure some will lose their jobs but I think half is overly pessimistic.