Twitter/Reddit does not seem to showcase the best case of critical thinking from younger generations either, so not sure if that is even a factor at all.

It turns out we're mostly all just morons.

Use of leaded gasoline was very high when someone that is now 80 was a child and young adult (~1940 to phase out beginning in mid 70s).

There were many more automobiles post WWII than in the era prior also.

Better nutrition and medicine have to be a big piece of it.

Smoking, too. Not just that people smoked themselves, but 75 year olds in the 90s retired from smoking workplaces; restaurants had smoking areas; bars were smoking areas. You could smoke on planes until 1990.

I’m a gen-xer and when I was in my undergrad the lecture theatres had ashtrays beside all the seats. You couldn’t use them at that time, but I knew PhD students who said they were able to in their undergrad.

Indeed, I remember sitting in the non-smoking section of an airplane, one row behind the smoking section where everyone in that row was smoking.

A lot of good that did me!