I just don't see people actually wanting this technology
Yes, I can't imagine anyone who'd rather be able to nap, read a book, or do anything other than staring at the bumper in front of them during a regular weekday commute.
You missed this other part of gstoddart's comment:
If I need to be paying attention every second in case the computer does something stupid (and need to be able to anticipate every point at which it could do something stupid), it will require as much or more attention as if I was driving anyway.
Maybe you shouldn't be commenting on Slashdot while napping, reading a book, or anything else...