There are valuable human activities which require the motive of money-making and the environment of private wealth-ownership for their full fruition. […] But it is not necessary for the stimulation of these activities […] that the game should be played for such high stakes as at present. Much lower stakes will serve the purpose equally well, as soon as the players are accustomed to them. (John Maynard Keynes, The General Theory of Employment, Interest, and Money, New York: Harcourt, 1953 , 374)
This quote from John Maynard Keynes suggests that while a capitalist economy requires incentives to function, the magnitude of these incentives is variable. This suggestion puts Keynes at odds with the conventional wisdom in economics today. The latter includes the idea, eloquently presented by Joe Heath in his EJPE article, that there exists a rigid trade-off between economic efficiency and equity: If, as a society, we try to make wages more just, we will necessarily thereby undermine the efficiency of the market.
I shall argue that this conventional wisdom suffers from an important blind spot, which can explain why it overestimates the rigidity of the equity-efficiency trade-off. This blind spot lies in the fact that economists take as given the labour supply preferences of economic agents, rather than treating them as a variable of their analysis. To see why this matters, we need to introduce two concepts: reservation wages and economic rent.