True, although the life expectancy of someone 50 years old today (in a developed nation) would surely be well over 80, so there has been some improvement at the upper end.

Thanks to a lot of expensive geriactric drugs, pace-makers, etc., modern hospitilization and nursing home intervention. This postponement of death isn't getting any cheaper and won't prevail much longer in a declining petroleum regime.

Note on lifespans.

From a purely population point of view, medicine is almost irrelevant (of course, on a personal level you may need medical intervention to survive). The greatest boon to health in our society is clean water, sewerage, food, etc.

If you are considering a downslope in living conditions, then basic hygene and sustenance are your key factors to staying healthy. Childhood and adult diseases killed enormous numbers of people in western countries (1 in 1000 and more per year for some of them) through till the late 1800s/early 1900s, thanks in large part to sewerage systems that were completed in major cities.

"You can never solve a problem on the level on which it was created."
Albert Einstein