And yes, no radars or seatbelts or RBTs and worse roads, yet no more fatal accidents than these days.
And compulsory bicycle helmets (motorcycle helmets too - I remember when they were optional in NSW, probably other States too, but I don't remember), child restraints, lower speed limits, safer intersections (traffic signals and roundabouts, even Stop or Give Way at almost every intersection), graduated licences, capacity and power restrictions on cars and motorcycles, motorcycle rider training, compulsory test for motorcycle permit and licence, the list goes on ......
What's gone wrong? Nothing.
If the VIC 1969 crash rate was applied to the 2017 population, it could (would?) have resulted in 1,933 deaths. There's probably around 900 people in VIC that are alive today (assuming they didn't die of other causes) because they didn't die in a motor vehicle crash, and it's probably because of one of or a combination of the above safety initiatives. I'm sure other States will have similar results too.