Umm........ Many, many, many, many more drivers today WEAR A SEATBELT. In fact, a lot of places have seatbelt laws.
Fewer fatalities just because of the cars? Or because of more people being belted in? ......Kinda blows up your argument.
I don't buy into the argument that ALL newer cars are safer than ALL older cars...
Example: a driver in the proper seated position wearing a seatbelt -
1974 Imperial vs 1998 Neon - a rollover accident, I would rather be in the Imperial.