You are right and yet as our lifestyle has become more sedentary with more processed foods our life expectancy has gone up and up. Perhaps this is the end of it, we are coming to a tipping point and it will begin to decline. But so far I see many reports of imminent doom and yet we continue to live longer than ever.
I think that the increased longevity you mention is not so much the result of better overall health as it is the result of being able to keep sicker people alive longer.