There's still too many involving normal sedans, at least in Australia. And modern sedans are sacrificing visibility for aerodynamics / fuel efficiency. So having them being blanket mandatory is the only sane thing.

They are still not a guarantee against these incidents, I personally added backup sensors to my previous car - a Subaru Outback. They saved me from reversing into another car that had kind of snuck up on me once.

The Tesla Model 3 (Ryzen '22 w/radar edition) is far, far superior in all aspects of safety when reversing now. Both a huge responsive massive FOV screen with side displays and the ultrasonic sensors beeping.