But the main insight was that since resources were scarce and had alternative uses, allocating said resources efficiently is the central task of economics.

Economics has, since WWII, primarily focused on the unit of measure, specifically dollars in the US. I often compare this to cutting down all of our trees to create rulers and measuring individual success by the number of rulers they can collect.

When we realize that the dollars available are infinite the allocation of "real" resources will again take a position of prominence. Individual wealth is only measurable by the utility of resources that can be purchased, regardless of the amount of currency available to do so. Inflation is the only constraint on currency creation and that is far more dependent upon resource availability than any arbitrary number used to describe the economic state as measured in currency.