Marginal thinking is useful on the demand side (that's what the marginal revolution was about). But it makes absolutely zero sense on the supply side: for pretty much every business, upfront costs dwarf marginal cost of production. Think of most businesses: the salaries are negotiated in advance, you must order stuff to your suppliers before you can sell them and all the CapEx is spent before you can use the productive capital. The cost of producing one more item with what you already have paid (inputs+workers+capital) is pretty much zero.
What makes sense if working on average costs, and that's why it's the metric that is being used by every real companies out there.
But then you can't show the nice graphic showing supply and demand curves nicely crossing each other at the equilibrium price anymore…
Economists should have ditched Ricardo's view of the supply side long ago like they did for the demand side (labor theory of value was crap and was rightly abandoned).
What makes sense if working on average costs, and that's why it's the metric that is being used by every real companies out there.
But then you can't show the nice graphic showing supply and demand curves nicely crossing each other at the equilibrium price anymore…
Economists should have ditched Ricardo's view of the supply side long ago like they did for the demand side (labor theory of value was crap and was rightly abandoned).