whether or not they utilize their time for gathering up retirement savings is not the issue. the problem exists, possibly one of the largest expenditures of modern states in the healthcare sector is taking care of the elderly. in america you have medicare etc (which as you know is going bankrupt), in the UK you have similar problems. Everywhere they are worried about the cost curve. And so you have the state investing in solutions such as robots/sensors that look after the elderly in their homes, alert medical folks when they fall down (because there have been cases when people remained unable to get up for days). This is all very expensive research, but its a drop in the bucket compared to the projections they see for elderly care in the near future.
there is therefore a significant economic cost in the fact that families do not stay in the same house for generations.