The struggle for life
At present, life expectancy is increasing at about one year for every five years that pass - only 20% of what is needed to keep our expected remaining years of life increasing at the same speed with which we age. That said, it is worth remembering that life expectancy is a statistical construct based on past data - it is a helpful measure of progress, but not necessarily an indication of where we are now. I suspect it lags present medical advances, for example, because their effects on mortality rate might not show up for a decade or more.
That is to say, conventional life-expectancy figures aren't a good guide to how long a person who is now middle-aged can actually expect to live, even assuming only present-day technology. It's more a measure of past progress. Remember also, of course, that most such figures are national averages which are pulled down by the obesity epidemic and by the shrinking but still substantial number of smokers. Realistic life expectancy for healthy people is probably much longer, and increasing faster, than conventional statistics would suggest.