I addressed that by saying the islanders could work on infrastructure and labour saving tools while young. That's investment, deferred consumption. However, th

I addressed that by saying the islanders could work on infrastructure and labour saving tools while young. That's investment, deferred consumption. However, this has limits. A country with a 8:1 worker:retiree ratio is currently much more productive than a country with a 2:1 or a 1:2 ratio. Maybe savings could change this for the future, by really making something that hardly needs labour. But presently we have a real labour barrier to this kind of saving. I agree it would be better if we saved more though, as this does indeed translate to invest. I hadn't explicitly spelled this out, so thanks. The islanders are indeed better off if they defer. But, they cannot make themselves so well off as when their society was young, and they still need some labour.