> do full-body work-outs a lot, eat a really clean diet, avoid drugs
Could it be that older people were less likely to be able to avoid physical work (even their chores were far more of a workout), were relatively more religious and conservative than current generations, and grew up with fewer processed foods and more home cooking by stay-at-home moms? What I mean by this is are you just describing people who were born in the 1930s? The fact that the ones that are left are mostly typical would be expected.
> keep using your brain actively into your 80's and 90's.
This could be seen as a symptom of aging well, rather than a cause. People whose brains don't work well aren't studied as examples of aging well.
The person I know who most fits this description is my dad, he had a swimmer's body in his 60s, worked out every morning since high school, has kept a dead center BMI his entire life, has never done a drug and probably only had a sip or two of beer, always had a gym guy diet that has gradually become more vegan, and was a math major and computer programmer, plays chess etc..
He's totally falling apart in his late 70s and becoming very frail. Seems like he's having nerve and neurological issues, and having problems with his connective tissue and with arthritis in his hands and knees. I don't know how you eat, work out, and think yourself into avoiding that. Half of his joint problems are caused from having been athletic, just like my super-athletic Army grandpa, whose knees would bend backwards for the last years of his life from football when he was young.
Protestantism isn't a law of nature. You aren't automatically rewarded for sacrifice and suffering, at least while you're alive.