The funny thing about retirement: Nobody was ever actually supposed to retire. Let's take the United States as an example. While the Social Security Administration will tell you that the 1935 decision to set the retirement age at 65 was based on the pension systems already in place at that time -- half of which had 65 as their retirement age, and half of which used 70 -- it fails to mention that Americans' life expectancy was a paltry 61.7 years at that time. It's almost as if the pension industry asked cold-blooded actuaries to design highly promising, Ponzi-scheme-like retirement programs that would only benefit a fraction of the people paying into them. Almost.
But then, wham!, bam!, penicillin became widely available, and by 1950, life expectancy had jumped to 68.2 years -- comfortably beyond the retirement cutoff. In 1952, Jonas Salk introduced a polio vaccine, the 60s saw vaccines for measles and mumps, and in 1967 the first heart transplant was performed. Americans began living healthier and longer lives. Increasingly spry older people were no longer reminiscent of the sad old horse that (spoiler alert!) gets shipped off to a glue factory at the end of Animal Farm.