He was only doing 95mph at the time of the crash. How many people here drive at that speed on the motorways and don't give it a second thought?
Having seen and read all of that it hasn't changed my opinion on tracking cars at all. Driving cars fast is inherently dangerous, however these sort of failures can happen just as easily on the road as on the track. Track safety is all down to the marshalling IMHO, which is why I go with the same companies over and over again (Bookatrack, MSV) and avoid others that I have personal experience of being utterly sh*t (Circuit Days). You will always get one ***** on a trackday who is out there trying to prove something, but careful, quick and decisive marshalling should stop an incident before it happens. On the odd chance a marshall fails to see something that you do (overtaking on a corner), then it's up to you to go and report that person and not just sit in your car fuming: So many people I know do that instead of complaining.
That said, this was just a mechanical failure that could happen to anyone at any time. It's horrible to watch, the guy was very lucky, but more accidents happen on the roads than ever happen on track.