Prevention is not about age related diseases, but early onset cancer, diabetes, high blood pressure caused by alcohol and tobacco use, unhealthy diet, and sedentary lifestyle.

A significant amount of cases could be prevented before they need medical intervention (and put burden on the medical system). There are several researches about this, the number of people with type 2 diabetes doubled in the past decades.

This is why some healthcare systems reward for example doing 10.000 steps a day with lower insurance fees. They recognized they save a huge amount of money if they get people to move.