Current economics assumes a world of unlimited resources, unlimited wealth. No matter how rapidly a resource is used, either (i) “They” will always find more, or (ii) substitute resources will always be found to serve to any required extent as well or better in place of the depleted resource.
Such conditions would characterise a flat world extending indefinitely in every direction, clearly not the world we live in. In such a hypothetical world, economic systems of any kind would be unnecessary. The very existence of economic systems on earth results from the fact that all resources, however abundant, are limited in five ways - in quantity, in potential extraction rate, in concentration, in accessibility and in renewal rate.
Read the rest of Limits to Growth?