I think the biggest problem is that the majority of drivers are ill prepared for when something goes seriously wrong and I'm not sure how you would go about doing anything to rectify this.
Also how often do you see this "modern" trend ... to drive with one hand draped over the wheel at 12 o'clock and body squint in the driving seat to allow this? In an emergency where large movements of the wheel might be needed to maintain control these people have no chance.
Braking distances from high speeds are a purely theoretical figure from the highway code in most people's minds. They have little idea of what the reacting/thinking distance and then actual braking distance looks like on the road.
Of course how you go about providing training to this level of competence I don't even begin to make a guess at. However I think there is a good case to be made for every learner driver to do a lengthy session or two on a skid pan so that, even if they fail to become proficient, they do at least know what it feels like when the limits of adhesion and breakaway actually feel like which might reduce the "panic" reaction and enable a measure of control to be achieved.
I think that when young, none of us are ready for things going wrong, in any thing we do. We can only learn from experience, either our own, or observing others. A motor vehicle has a greater ability to maim or kill us than most of what we do daily. I suppose having a parent with poor driving skills might be a benefit here?
I think it is a modern trend to drape a handover the wheel. No idea where it comes from. Unless it is 'cool', so propagates from that.
Braking distances in the highway code are not particularly valuable. Even if we learn the numbers, few of us can visualise it. I will ask my learners about such things, then ask them to look ahead (when stopped) and identify something that distance ahead. None have had any idea where to point yet. I readily admit, I couldn't either.
A practical demonstration is needed.
I'm lucky, having a nice country road nearby, several straight stretches, little traffic. Off we go at 30mph. The at some time I say, "STOP". And we stop. Leave the car there, and walk back to the 'stop' point. Now you can see exactly how long it took to stop, and anything between will be hit.
Depending on experience and competency, speeds can be increased. 60mph brings a long walk, and 70 or 80 is quite an eye-opening distance. Very sobering, and has been useful in helping many control their speed, and extend their view ahead, both over-exuberant learners, new, and experienced drivers.
I doubt many get this opportunity.
Skid pans are great fun, but scarce. When it snows, rarely here, I have a large car park I use, to get the learners sliding. It is an unusual car park, with no kerbs, posts, trees, flower beds, etc. Speed is kept to 15-20mph, and they are encouraged to accelerate, brake and steer until they reach the limits of adhesion. Then combinations of steering with braking or accelerating. Nowhere near as good as a skid pan, but better than nothing, and free when the weather provides. When we do get snow, I'll call past learners and encourage them to come out to play, some do.