Its an average. An average. It doesn’t mean there aren’t some people who are going to live long lives.
The average of those times had more infant and childhood deaths. Further, the more elite/higher you were in society, the more likely you’d live longer. Better food, better care, better shelter, less dangerous work.
No Schiff Sherlock, that’s the point.
Acting like most people didn’t live to 40 or more years old as your comment suggests is stupid.