It may also be worth noting that one of the major things that has caused serious (for this I see it as career threatening) injuries to GC contenders in Grand Tours or preparation races in the last five years has been crashing on Time Trial bikes (Froome, Valverde, and also Van Aert and Lopez to a lesser extent if you add in super domestiques). I know UCI rules on bike design are often spoken about as a joke in the press and some kind of unjustifiable brake on the engineering 'brilliance' of the major bike brands, but this seems to be an obvious area where having rules in place that ensure that bikes handle well enough to stay upright probably has stopped more crashes happening, and also perhaps somewhere where more can be done still.
I really like that thought, time trial bikes and the building of the bikes in general are a bit overlooked when it comes to crashes.
I also liked the idea (don't know who suggested that), that you should have raced U23 for some time as a "qualification". One might think more in that direction, what can be done to improve the bike handling skills and experience of inexperienced riders, a certain mandatory step system or something like special preparation races - I think it might be a problem that especially the younger, more inexperienced riders are often sent to smaller races where the safety is not as good as it's usually at the biggest ones.
Also maybe at least one winter of cross or a summer of mtb should be mandatory...
I don't know, I'm just going bonkers here, but I'm serious about the general idea: I am really sceptical about more and more riders skipping the U23, more people coming in directly from other sports or Zwift (some like Roglic might have extraordinary balance, but that doesn't make them necessarily good in a peloton, and others don't even have great balance, they just have the watts)... and I think something should be done to counter that, to give those riders more experience on the bike and on the road.
The list RedheadDane made, though, shows that sometimes it's just really, really bad luck: like Lambrecht
The biggest problem in my eyes are not the races though. It's the training, where so many bad crashes and accidents happen, usually with cars involved. I don't really have a short-term solution for that problem.