Understanding excess supply

Over at Econospeak is a fascinating conversation of arcane economic thinking:

Peter Dorman at Econospeak states:

I have just taught the theory of the supply curve at the principles level for the umpteenth time, and my conscience is in open rebellion. This business with the horizontal demand curve and setting supply equal to marginal costs is simply rubbish; it denies some of the most important, and obvious, facts about how capitalism actually works.

At the level of an individual firm, the theory obscures what ought to be the starting point for analysis—that in a capitalist economy the normal state of affairs is that firms set production at a level that requires them to chase consumers any way they can, and that the usual result is that some offerings go unsold. Across the entire economy the level of activity is nearly always demand-constrained, not supply-constrained.

Consider the relationship between buyers and sellers at the level of individual enterprises. From observers like Alec Nove and Janos Kornai, we have come to recognize that the prevalence of buyers’ markets is what distinguishes capitalism; in the state-managed systems of pre-1989 socialism, the seller was king. This suggests that excess supply is the most likely state of affairs, excess demand the least likely. An exact equality between demand and supply at the market-determined price is essentially impossible.

Nick Rowe at Worthwhile Canadian Initiative responds thusly:

Just to be clear, I totally agree with your first 3 paragraphs. It bugs me too. But my solution is different from yours.

(here as well in pictures)

Update: Nick sends Angry Bear an update to refine and illustrate his point here.