Why not just do as you suggest ("kick off the radio, turn off the AC, sound and alarm, or even just pull the car safely to the side of the road") if the driver

Why not just do as you suggest ("kick off the radio, turn off the AC, sound and alarm, or even just pull the car safely to the side of the road") if the driver isn't paying attention? You can still do all that you suggest while providing semi-autonomous driving capabilities.