Are our Slants "Unsafe"?

I won't deny that cars designs are safer, but that is only because people are in a hurry, rude, imprudent and self centered.

No, it's because every type of engineering has evolved based on more and more knowledge, better and better tools.

Back when our A-Bodies wer new people were still bad drivers just not as bad as they are today.

Disagree. Today's drivers are differently bad than yesterday's, is about all. Drunken driving was laughed off, nobody wore seatbelts, and carbon monoxide levels in any kind of dense traffic area were so high that everyone was operating while impaired.

cars have changed in relatively few ways

That is not a supportable statement unless you're pointing out the obvious fact that they're still metal boxes on four wheels, usually powered by a gasoline or diesel engine. Other than that, virtually everything in terms of technology and technique has changed, and if you make the comparison from the relevant angle (actual safety performance) then today's cars might as well be Jetsons items -- they are that different and that much better than yesterday's.

No amount of talespinning or handwaving makes yesterday's cars anywhere near as safe as today's, in any kind of crash. They just plain aren't. Not in the real world.