As life expectancy is increasing due to advancement in medical science, people are left with more years after their regular income stops. With increased age comes increased expenses in the form of healthcare expenses, which will occupy the greatest share in spends pie-chart.
You would need a retirement corpus to finance your increased expenses as there would be a complete absence of regular income in life.
Increased life expectancy -> Rising share of health expenditure -> Need of a retirement corpus
” Increased life expectancy comes with a cost, and everyone has to bear the same “