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.
but most deaths occurred in first year or two. doesn't takemany of those to drive down the average. and then there is the stupidity of adolescence and war.
