An economist looks at his profession and finds it wanting. Economists today tend to believe that their subject is the most rigorous of the social sciences. After much time and study they have developed complex equations, which they can manipulate extensively in modern computers, turning out solutions to complicated questions in precise detail. The answer, in one sentence is that their theoretical models don't have much to do with reality. Prices are not determined by supply and demand or by competition among producers.
Comparison shopping is impossible.
Greater productivity does not lower costs. Sometimes, in fact, the system works exactly opposite to the way of the normal marketplace. For example, the providers of the service, doctors and hospitals, determine how much of their service their customers will buy. Their customers, the patients, can rarely evaluate the quality of the service they are receiving. This is one reason medical costs are rising out of control.