Why life expectance is growing faster than retirement age? - source needed Need sources of information about "Why is life expectancy growing faster than retirement age?" 

Is there any literature about "why the increased quality of life and medicine in rich countries doesn’t increase the ability to work for older people?"
Loss-aversion and political tactics.

A lot of the elderly are no longer physical broke down - which was the original reason for retirement. But, if you can retire in good health, it is completely rational for the individual to do this, and to vote for the politicians who will provide this for you. 

Or, as a danish mayor once put it: 


  "When you first throw something into the monky cage, it is hard to
  get it back again"


Aka, when you first give people major entitlements and life improvements, it is next to political impossible to take them away.