There are people whose only exposure to a desktop computer occurs when they are in their local bank branch, cashing cheques at the human teller booth. Even this is not direct exposure, because the interaction with the computer is mediated by a trained human operator. Such people are totally unreachable by task-oriented computer training because these people simply do not understand what a computer is for , or why they would want to use one. Even if computers are in fact easier to use than cars, the cars still win on total usability simply because cars have effective training infrastructure and experience already in place and computers do not. Computers, for some reason, cause people to lose their basic common sense.
People seem to expect that they can make effective use of a computer without any prior training.
This notion is completely absurd on its face. There is nothing that a user interface can do in the short term to assist a user who does not understand the basic concepts of manipulating information, yet for some reason modern computer interfaces are intended to do exactly this. Cars do not routinely distract a driver with animated paperclips that indicate when turn signals should be used in traffic. Drivers do not demand this kind of feature because it is entirely useless when it's not measurably counterproductive. But for some reason this is accepted as normal when it comes from a computer.