Why So Little Competition?

Ezra Klein editorializes on health care. This is an important point:

In the modern health-care system, there is no higher power than the insurance market. And the insurers who populate that market have grown all the stronger. The Justice Department judges an industry "highly concentrated" if a single company controls more than 42 percent of the market. By that definition, 94 percent of statewide insurance markets are highly concentrated. A recent study by the advocacy organization Health Care for America Now showed that in Indiana, WellPoint controls 60 percent of the insurance market; in Iowa, Wellmark accounts for 71 percent; and in Alabama, Blue Cross/Blue Shield holds 83 percent. In the past 13 years, there have been more than 400 corporate mergers involving health insurers.
Economics textbooks tell us that concentrated markets reduce the competitive behavior that benefits consumers and lead to outsize profits for the dominant firms. Predictably, health-care premiums shot up more than 90 percent between 2000 and 2007, while the profits of the 10 largest insurers increased 428 percent over the same period. Clinton had promised us managed care within managed competition. Instead, the insurers took control of our care and managed to effectively end competition. Neat trick.