This Chicago-style approach, sometimes known as ‘Price Theory’ because of the fundamental role that prices often play, is exemplified in the path-breaking work of Gary Becker, Ronald Coase, Milton Friedman, Sherwin Rosen, George Stigler, and many others. Price theory has shed light not only on the most fundamental topics of traditional economics (e.g. consumption, saving, taxation, regulation), but also pioneered the use of economic tools in studying a wide range of other human behavior (e.g. crime and corruption, discrimination, marriage).
Becker Center on Chicago Price Theory, "Mission statement prior to the inaugural conference, April 2006," as cited in: Shoshana Grossbard, "How “Chicagoan” are Gary Becker’s Economic Models of Marriage?." Journal of the History of Economic Thought 32.3 (2010): 377.
Economics is that way of understanding behavior that starts from the assumption that people have objectives and tend to choose the correct way to achieve them.
Essentially the fault lies in the fact that the democratic political process is at best regulated rivalry; it does not even in theory have the desirable properties that price theory ascribes to truly competitive markets.
Some of post-Keynesian price theory comes forth from the belief that universal competition is a bad assumption. I have all my life known that. So I have found it an unrewarding approach and have not paid much attention to it.
Early in my professional life, I found that many areas of economics attracted me. I started working and publishing in price theory by 1938. In 1946, I published an early work on linear programming (The Cost of Subsistence) which solved the problem only approximately; George Dantzig soon presented the exact solution. In the 1940s, I began empirical work on price theory, starting with a test of the kinked oligopoly demand curve theory of rigid prices.