Today, in an average industrialized country, men can expect to live until they are 75 and women until they are 80. A hundred years ago those numbers were 50 and 55. Today around 13% of the population does not live beyond 60, a hundred years ago it was 63%.
So in the span of 100 years life expectancy has increased 50% and there is no reason to expect this trend not to continue, perhaps not at the same pace, but with continued improvements in living and working conditions, health care and nutrition people will continue to live longer. But, while people will live longer it does not necessarily follow that people will stay fit and healthy for longer.
Generally as societies get richer, life expectancy goes up while birth rates goes down. This causes a shift in demographics towards an ageing population and eventually a declining population. Keeping the current retirement ages will mean more people will need to be supported and for longer with fewer people to do it.
Raising the retirement age is inevitable