When a ressource gets rares, prices go up. This drives big incentives to work on substitutes, recycling, higher efficiency, etc.

Ex: People were predicting Peak Oil is the end of our civilisation. Turns out there is plenty of oil deep in the seabed if you are willing to pay $100 per barrel. In turn, $100 barrel push hard on consumers to use more efficient vehicles.

Market prices are a powerful signal that causes everyone to adapt.

Large populations have lots of interactions, which is good for innovation and commerce.