I get what you are trying to say, but your figures are a bit off. In the last few centuries (outside of war/famine/et), if you made it to "adulthood" (depending

I get what you are trying to say, but your figures are a bit off. In the last few centuries (outside of war/famine/et), if you made it to "adulthood" (depending on the statistic 15-20 years old) and were male, you had a reasonable likelihood to live until "old age" (late-60s to early-70s). The problem is making it to adulthood wasn't straight forward. Until the 20th century, your likelihood to make it to adulthood was only 50/50. There even if you made it out of infancy, child labor, disease, food affordability, etc., were all major causes of death. Making it to adulthood meant that you were lucky or privileged. Now for calculating retirement ages for individuals who were adults when they started working, sure, the life expectancy has basically been flat. Maybe a few years of uptick, but nothing substantial like it seems looking at the overall stats of going from 45 to 75.