I think the risk information given to skiers is pretty thorough.
You hardly ever see an accident without a cause.
It's usually something like ignoring the avalanche warnings, or ignoring the Stay On Piste signs, or not checking the weather reports which are posted at all the lift stations.
You hardly ever see a serious ski accident where the skier was on a marked piste in good weather. Sure, we all get bumps and bruises, sometimes, fractures, but the last time a sport put me in hospital it was mountain biking. As I went over the front of the bike, a pedal went through my shin.
Michael Schumacher was not on a piste, and he was going extremely fast. We all take short cuts between pistes, but you have to be careful. If you're off piste, you ski "tips up" and ride the snow. MS was skiing flat out, tips down, and hit an obstruction under the snow.