Or even if you're uninjured. young and healthy, but in the front seat, strapped in, disoriented, and tangled up with debris. I'm pretty flexible for someone my age but I doubt I could pull off that trick starting out from the driver's seat. In fact, I doubt most people couldn't.

The point with this obsession with technical solutions is that they often tend to make the systems more complex, which means more prone to failure. The failure isn't necessarily mechanical, its because the human gets confused when things don't go the way he expected. Or if he fucks up.

Yes it is possible to devise technology that can help, the seat belt itself is an excellent example.
But the simpler the better. Complexity will always bite you in the ass. And all technical fixes tend to give you a false sense of security.

I haven't heard the one about the rear window, the story I heard was that all modern cars are equipped with a switch that when it is submerged, automatically rolls down all the windows. I don't believe that either.

My new car is all electrified (doors, windows) but the mechanical door handles in the front override the electric locks. Once the car is full of water and there is no pressure differential, THEN you can open the door and swim out. Its the same in the back doors, but the driver can override the override so that kids in the back seat can't go for a walk while the car is moving. Unfortunately, if the owner forgets to disable that feature, I suppose the passengers in the back seat can wait for the car to fill up with water and then can kick out the rear window.

Norman Mailer in his "A Fire on the Moon" devotes a whole chapter to this fallacy entitled "The Psychology of Machines". In his example, he imagines that the designers of a spacecraft install an emergency oxygen tank, valve, hose and mask for each of the two crewmen, in case there is a failure in the O2 system. These two parallel systems offer redundancy, but if any of those components fail one astronaut will die, so the designers connect the two systems and install bypass valves, a manifold, multiple hoses, and even an additional mask. The whole arrangement can suffer enormous damage but can still do its job by the crew isolating damaged components and sharing those that are still functional. Unfortunately, the system is now so complex (A tangle of pipes, hoses, valves) that it takes an enormous amount of training and practice so the crew can master this bundle of snakes even if they are dealing with another emergency (like a fire in the spacecraft). So a computer monitoring system is installed with sensors and servos to be able to manage the system if the crew is busy or incapacitated. Of course, the emergency O2 system is now so complex that it must be tested periodically so the crew can keep up with its complexities and exercise all its components. This testing protocol now has to be documented, which means constant monitoring to keep track of wear and tear, oxygen consumption, and that information must be relayed to mission control through telemetry. And so on, and so on.

My old boss in the Navy once quipped, "Radar is great, but ships still collide, even in broad daylight. Sometimes you just have to take a look out of one of those little round windows."