The span of human life has been constant for millennia, between 25 and 30 years. Yes, there were quite a few people that reached an older age, but the infant mortality was so high that on average the life span was pretty short. Maternal mortality was also high and statistically that happened on the third childbirth.
In the first graph you can appreciate how "stable" lifetime expectancy has remained for millennia. A dramatic change happened about 3 centuries ago with the invention of ... water! Purified water, that is.
Purified water was the single most important factor in curbing infant mortality and hence increasing the average life expectancy.
More recently, the advent of antibiotics (in the middle of the last century) further boosted average life expectancy, and even more recently better food availability contributed to the extension of life expectancy.
Availability of food and better hygene, along with economic means, is different in different Countries and this clearly relates to life expectancy, as shown in the third graph.
Also interesting is the increase in life expectancy that has been achieved over the last 30 years, as shown in the fourth graph, measured once one has reached 65. Here the progress in medicine is probably the leading factor in the increase and it is interesting to notice that this increase is expected to continue in the next 30 years. However, on the average, even by 2050, life expectancy once reaching 65 is to live till we will be in our nineties (up from the middle eighties of today's expectancy).
A host of technologies will foster this increase in the coming two decades, better surgery, less invasive and more precise, stem cells, genomics leading to personalised medicine.
ICT is likely to play an important role, particularly the capability of learning from "big data analytics" to pinpoint epidemics (these are likely to become rarer and rarer because of their prompt detection in the early stages) and to better pharma effectiveness (and pinpoint potential side effect) with symbiotic IoT providing both continuous monitoring and release of drugs as needed, when needed.