In nature after an evolutionary collapse, mother-nature will begin to rebuild, and in a normal business cycle so too would an economy. However in a boom and bust cycle things are not quite so easy!
The starting point for all of economics is excess. In a time before money, being able to produce more than one’s own immediate needs lead to the emergence of barter. But with the introduction of money – which acts both, as a means of exchange, and a store of wealth – “excess productivity and production” could lead to the accumulation of “disposable income”; and it is this disposable income that drives all economies in 2 separate ways
Consumption: disposable income drives trade, and thus economic activity.Investment: disposable income drives innovation, and thus economic complexity.