The term "Life Expectancy" is a scientific measure of how friendly an environment is to babies. That is all it is. The time of Moses notes that people lived three score and 10 (70 years) with some living four score (80 years). This meant most adults died between 70 and 80 some 3 Milena ago or more (depending on who you ask). The average life span for a woman in the United States is 82 and a man is 78. When you average those together you are still between 70 and 80.
What makes the Life Expectancy go up over the last 1000 years is infant mortality. The reason Life Expectancy is so low in the third world is infant mortality. If half your babies die before the age of one and everyone else lives to the age of 80 then your Life expectancy is 40. You can clearly see that this doesn't mean people are dieing at 40 it means the average life expectancy is forty do to the fact that half of your babies are being averaged in at less than one for every 80 years old making the average 40. As less babies die before the age of one the average comes up. As most live to their potential then the average falls to three score and ten with some living four score.
But this measure is arbitrary and has a lot of assumptions. It only averages babies that die from accidents and natural causes. Abortion and miscarriages aren't factored in. Clearly real Life Expectancy; how old you might actually live, has not materially changed at all. Rather more people are likely to get the full experience of three score and ten with some living four score. Which can be argued as improving living conditions and even quality of life but claiming it is extending life is a bit over the top.
Even in antiquity there were exceptions, people who saw 100 years but they were the exception that proved the rule: most people live three score and ten with some living four score. Of course this old measure didn't count dead babies in the math. It merely made the observation as to what age most people died. Over eating and lack of exercise is still a major problem in this country. Overeating and lack of exercise is an adult problem not an infant problem. And its effects are minimal compared to dieing less than a year old on the result of an average.
When I see the average life expectancy clear and walk away from the three score and ten with some living four score rule, then I'll believe we are extending life until then Its the same stuff that causes you to buy anything; Marketing.