[Taywee]

I don't think the top level comment was inherently about money, though. "Contribute back" can mean non-monetarily, or even be implying an indirect monetary gain from them contributing non-monetarily to their families.

Economics is devilishly difficult to really efficiently predict. More reliable lifespans and a larger elderly population can affect the total flow of money in ways nobody can properly imagine, positively or negatively.

From a younger perspective, the effect of eliminating cancers from the equation implies a lot. What is more expensive to the world, years of cancer treatments and palliative care to somebody in their 70s, or somebody living healthily through to 90 years old before dying from heart failure? What about the family cost of caring for a sick elderly relative?