Good example. So, why can't AC do something to limit its risk?
What risk? In many races around the world (AC series) with many boats with many accidents and many sailors involved nobody got seriously injured. Regarding the development of the bigger boats only two accidents and an unfortunate dead.
Racing in any discipline that involves speed has risks and people die accidentally doing that. People die too crossing roads. Racing has a bigger risk than crossing roads it all has to do with what is an acceptable risk, for crossing roads and for racing. One accidental dead in all AC campaign, included all the races on the AC series don't seem to me the alarming and excessive risk you seem to believe exist, in what regards racing. Facts do not point that way, at least yet.
Maybe the substitution of automatic PDFs by manual ones can be enough to prevent or diminish greatly rare accidents like this one.
One thing is for sure the AC is not anymore a race where old millionaires could be part of the crew and even steer the boat while racing, like on the other editions. This one is for athletes on the top of his physical and mental abilities and that is one of the changes that this AC brought to the sail races. It is a good one. Racing at top level should be like that: something a "normal" sailor could not dream of being able to do something about one should ask: "How the hell can they do that?".
That is what happens on all other speed racing sports and in that aspect Chief is right when he refers racers going downhill at 100km/h around bends on a bicycle: "How the hell can they do that?" and also regarding risk, to understand that the risk exists but what would be a deadly one, if you or me where on one of those bicycles around bends at 100km/h, it is a manageable one when on that bicycle is a top racing cyclist. That does not means that if he loses control and go against a tree he would not be as dead as me or you only that the chances of that happen are a lot smaller (but they exist).