I don't think there is much difference of the lifespan of today when compared to one hundred years ago. Unfortunately what IS occurring is that there are folks today who are living "prolonged' lifespans with diseases that took them out years ago. We are "extending" people's lives nowadays, but not necessarily increasing the quality of life to go along with it.
I have recently spoken with a good medical friend of mine in Melbourne, Australia who specializes in geriatrics and he said that there are a surprising amount of elderly folks he is aware of still living at home, with family, who are 100% drug free. Many are in the eighties and nineties. BUT - in most cases, they are of Italian or Greek descent and are well supported in a happy family environment. They are made to feel worthwhile and loved very much and respected. They still perform a valuable role as the "wise old one". Unfortunately, in our Western society, all too many "oldies" end up discarded and placed in old folks homes and visited once in a while. Depression, boredom and loneliness take their toll. It breaks my heart to see this happen, I love older patients and spend a great deal of time with the really old folks in particular. They have all the time in the world and so much knowledge.
Drugs are unfortunately dished out to anyone over fifty these days, and it is indeed rare for any person I see over 70 who is not on at least a statin drug or blood pressure pill. I have many patients however who do not take ANY drugs at an advanced age.
There are many recorded instances of people living 90+ in the "old days", in fact, my belief is that in many countries the lifespan is in fact in decline - like Japan, where the average life expectancy of a male was 77, but now is 72. Why? MacDonalds, smokes, more alcohol and an increasingly sedentary lifestyle. So much for "progress".