I believe what you're saying is correct, but the OP is also correct in pointing out that those who lived prior to antibiotics or other modern inventions probably died a lot more often of things we can prevent now. Not to mention all the routine surgeries that save lives. The massively declining child mortality is the big disruptor here, but there's more going on in the data. More recently, we might be reversing the positive trends with our extremely unhealthy diets that have led to other issues such as heart disease and diabetes.