Gawd I'm starting to feel old, it's all very laudable wanting to stop people from killing themselves, but the layers of cotton wool are starting to smother too. Where do we draw the line - mandate medicals for all (not 100% effective anyway), compulsory BRS, compulsory helmets, compulsory fire proof clothing, the list goes on... All would improve the odds of surviving in some circumstances, but do you really want Big Brother insisting? I don't.
The bottom line is that as pointed out in several posts above, RAAus accidents are investigated, just not always by the ATSB and the findings aren't published in the same way. It takes a small amount of effort on the individual's part though to read forums such as this, read the coroner's report if there is the remotest chance it may have a bearing on your operation, read the notices RA-Aus put out as referred to by Flying Vizla - the information is out there, just not spoon fed, so exercise a little personal responsibility and initiative, and seek it out.
In any event, the ATSB aren't some all seeing, all knowing clan of wizards either. Some of their reports have been less than brilliant and many have vociferously disagreed with their findings. Does the Great Jabiru Furball of 2015 ring any bells?
To expand on what I said in an earlier post, if I spear my tandem recumbent bicycle into the scenery at 100 and plenty, scribbling myself and AN Other - do we really need the ATSB to investigate and decide that I was riding like a goose, or that my home-brewed braking system was held together with cable ties and wishful thinking? I'd suggest not. Why then is private aviation so different?