Plenty died in their 40s and 50s from diseases we can now control, such as diabetes.
Yes, true, but actually probably the biggest threat outside an outbreak was pregnancy/childbirth. It is a terrible thing.
You’ll see lots of young WOMEN in the graveyards, about 20-30. Sometimes along with their “infant son”.
Bottom line is people who were pretty healthy and didn’t get unlucky other ways (accidents and murder) could make it up to the 80s.