If you were able to dispense with the cab and any human interfaces/amenities, that would cut out a big chunk of weight and drag. It would look radically different but just think of all of the components on a truck that are only there for the driver. No need for a cab, AC system, heater, pedals, steering wheel and linkages, airbags, seats, pretty much all of the glass and windows, doors, etc. The added sensors, telemetry, and computational requirements necessary for an autonomous vehicle suddenly don't look so pricy compared to the savings of removing a huge chunk of the vehicle, nonstop operation or maintenance, no salary for the driver, lower insurance costs, lower fuel costs, and other assorted savings. Really it's looking like more and more of an inevitability in my opinion. Once the control problem is solved, I doubt it'll be more economical to continue putting a trucker behind the wheel.

Of course if you need to provide all of that to allow for someone to drive it manually around town a lot of those benefits are gone. Who knows, there will probably be some transitional period where all automated trucks are still equipped for manual control but I doubt it'll stay that way for long.