If you consider a simplistic economic model then there should be no public pensions or healthcare at all. The moment that somebody's direct economic output fall

If you consider a simplistic economic model then there should be no public pensions or healthcare at all. The moment that somebody's direct economic output falls below a defined threshold, be it due to retirement, illness, lack of retraining in a changing job market, then they represent a liability to be efficiently removed. Fortunately more sophisticated approaches are generally followed, since in practice humans aren't simply worker ants or feedstock for Solyent Green.