If 24 people had been killed in an earthquake, cyclone, air crash, fire, industrial accident, mine or virtually any other way, news media would go berserk. As it is they were killed on the roads at Easter. If anything the deaths got slightly more attention than usual, because the holiday period has been otherwise fairly quiet.
The great tragedy is that nearly all the 2000 or so deaths each year on Australian roads (and the 20,000 or so injuries) are largely preventable.
It is true that the toll has dropped from a decade ago. It is difficult to say precisely why … probably a combination of better cars, better roads, higher penalties for breaking the law, more certainty of being caught and more compulsory safety requirements. The reduction in the past decade, improvements in accidental deaths and a general reduction in risk-taking activities such as smoking show it is possible to change human behaviour for the better and it shows that the effort is worth it because of the avoidance of human suffering and the economic advantages.
Technological improvements and legal enforcement are probably plateauing in their effectiveness, though the effort must continue. But more effort must be put into investigating human behaviour so we can understand why some drive in a manner that results in accidents and others drive in a way that avoids them, how to convert the former to the latter.