It's important to realize that there is a big difference between expected age at death when you're first born vs. expected age at death when you're retiring (whether at age 64, or 67 as is the case for US Social Security full retirement age).

For example, an American male has a life expectancy of 73.54 years at birth (https://www.ssa.gov/oact/STATS/table4c6.html). However, the American male's life expectancy at age 67 is 15.63 years, for an average age at death of 82.56. That's nine years later age at death, which is the real driver of funding retirement (for the obvious reason that if you die at age 60 you likely need no money for retirement).