The keyword is maximum. Yes, that can't be improved unless our genes have changed substantially in last few centuries. However average has improved substantiall

The keyword is maximum. Yes, that can't be improved unless our genes have changed substantially in last few centuries. However average has improved substantially. The massive number of diseases that used to kick in before genetically imposed maximum age limit including diabetes, cancer, heart attack, pneumonia etc have gone down significantly bringing average closer and closer to maximum.