When people are hungry, you cannot tell them "there's no food", or "we cannot harvest this resource now because it would be unsustainable". They need food now,

When people are hungry, you cannot tell them "there's no food", or "we cannot harvest this resource now because it would be unsustainable". They need food now, so they will eat fish before they reach reproductive age, kill the O-horizon layer in the soil, kill all the pollinators, pump all the groundwater, burn all the fossil fuels... because if you do it you will be rewarded with food in the short term. But then the people that depended on those unsustainable feeding capacity increases will have a hard time finding food.