Wouldn't all of that be true for my island society too, as long as the population was stable? Such a society would nonetheless face much difficult if the worke

Wouldn't all of that be true for my island society too, as long as the population was stable? Such a society would nonetheless face much difficult if the worker/retiree ratio changed from 100:0 to 20:80. That's true regardless of individual productivity level: case two is harder than case 1. Regardless of capital stock such as ports, rail lines, buildings, etc