I agree the theory is compelling. (If it weren’t, auto makers wouldn’t me trying it.) But...
I just watched a video of a chemist experimenting with a dangerous reagent that was delivered in a can with a standard pull-tab top. The can came with opening instructions. One comment was that if you can’t figure out how to open a pulltab can, you have no business playing with dangerous chemicals.
Similarly, I think, perhaps as you’re saying, if you can’t commit to being an active participant in the basic functions of your vehicle you have no business behind the wheel. Like so many technologies the implementation is getting ahead of the wisdom. Too many people are tempted to surrender to the tech because it’s neat-o and indulges laziness and inattention, two things you don’t want to amplify in a driver.
If we really want to make cars safer, we will create a system that coordinates all of their movements. You don’t need computer-level braking reflexes, for example, if the computer is controlling all the cars. But we don’t (yet) live in the world of Minority Report.