To me the issue is, irrespective of how competent an excessively speeding driver may or may not be, the thing you can't legislate for is other drivers, animals, unexpected issue, etc. Eg. a few years ago when I came round a bend on a country road in my Caterham and there was a brick in the road (a brick is a significant hazard if you are in a Seven) and there was a car driving the other way, so not much leeway for dramatic steering adjustment.