If you look back far enough for a point of comparison, technological progress has produced astounding results. Life expectancy at birth has in fact more or less doubled since ancient times. This is largely a result of reduced infant mortality and control of infectious disease, however, not any direct strategy of effectively tackling age-related disease. Life expectancy at 60 has climbed much more slowly than overall life expectancy, but it is nonetheless increasing at about a year every decade at the moment. This is an incidental increase, a side effect of general improvements in medicine; the clinical community is still not in any meaningful way trying to treat the actual causes of aging, the reasons why we become frail and diseased in old age. That will change shortly, is changing now in the laboratory, and past trends will shift radically to the upside in the decades ahead.
For thousands of years, the average lifespan of a human being was around 40 years. Evolution holds the explanation: it takes about two decades to grow up and be fully ready to reproduce. Then the offspring come along, and it takes another 20 years to get them ready to leave the nest and repeat the cycle.
"Biologically, we are programmed to live for 40 years, and if we had not been able to do so, the human species would have perished." The improvement in life expectancy over the past two centuries comes from the combined effect of a number of factors. "Sewage systems got better and limited the spread of diseases. Drinking water became cleaner. The industrial revolution provided more people with paid jobs and more money to spend on food and shelter. Housing got better. We got vaccination programmes and managed to limit the number of children dying. Deaths from violence also dropped dramatically as societies became better at organizing social order and protection."
"The importance of medical intervention has been generally overrated when it comes to past increases in longevity. To say that the invention of antibiotics is the reason we've expanded our life spans dramatically is false. Of course I am not blind to the enormous impact medical care and treatment can have had. There's no doubt that the decrease in cardiac deaths has significantly contributed to our increased longevity, but there's no consensus on the contribution of specific factors. Nonetheless, the development of human lifespan is an unprecedented story of success on a societal level, and we need to stop being pessimistic about people becoming older. We will live longer and better than ever, and we should each make it our mission to make the most of it."