How much of that life expectancy 100 years ago were affected by child mortality? We haven't really doubled our longevity, we just took care of some things that lead to a lot more children reaching adulthood. The bulk of that might have been pretty simple, like better hygiene.
Are you suggesting modern medical science not helping people live longer by treating Cancer, Organ Transplants, Bypass surgeries etc ?
I am seeing so much pessimism on HN , it seems unlikely that majority of people here are hackers.