Re: Transitional period
I see them as totally different things.
Traction control, ABS and power steering all have one thing in common.
Outright failure of the system cannot result in a more dangerous situation. If ABS fails, you still brake as hard as the brakes allow - but if you're don't realise that, you MAY skid more but no more than if the ABS just wasn't there at all.
(Note: Failures of the BRAKING system itself are another matter and very dangerous because failure of it DOES result in a more dangerous situation! Lovely having all this fancy tech but if you put water in the brake fluid, it's still useless)
Traction control - if that fails, again, you're back to "normal" driving.
Power steering - if that fails, you're back to heavy steering of old but still maintain control.
A short period of confusion, maybe, but if your ABS fails and you need to brake, you just hold the brake down and things still happen.
I disagree, therefore, with avoidance or removal of such facilities.
However, emergency braking? If that fails, that could perform unwanted emergency braking SUDDENLY (in spray, snow, slush, etc. as pointed out by other posters here). If cruise control fails, it could accelerate or ignore the driver's input entirely - it has control of the throttle.
It's all a question of if a tech is fail-bad or fail-good. ABS failures result in lights, warnings, and NO ABS but still hydraulic braking under the control of the driver (on or off). Emergency braking failures, however, result in pile-ups, accidents and deaths no matter whether the driver wants to brake or not. They may be one-in-a-million but I object - as a driver - to losing control over something that I'm ultimately responsible for.
Lane-veering warnings - no conceivable failure of the system can result in a situation worse than not having it. It might false-warn, or not-warn, but that's it. It shouldn't control the car, or snatch the steering wheel to put it back in lane (because, again, that's overriding the driver and dangerous).
As I've had to tell several bosses: If you want me to have the responsibility, I have to have the power to control all this stuff. If you don't want me to be able to control it, I don't want the responsibility for it. If something fails, it needs to fallback to the driver and normal systems. It should ENHANCE the car, not control it. If emergency braking fails - by definition, it has control of braking that overrides the driver. One sensor malfunction or bit of water in a cable, and it's going to push you into the hardest kind of emergency stop. Hell, even at speed potentially because the speed it sees is just a sensor again. Just because it says it can't operate over a certain speed doesn't mean it couldn't operate the brakes at any speed in the case of a malfunction.
And an unexpected emergency brake of your own vehicle at 70mph going round a motorway bend in four-lanes of flowing traffic is fatal, no matter the distance in front or behind you.