The first experts were shamans, an occupational category that eventually divided into doctors and priests. As the Catholic Church became more and more powerful, abuses of priestly power became more and more apparent and upsetting, leading to the Protestant Reformation.

Now — half a millennium later — doctors are under much greater scrutiny. The results of that scrutiny are unfavorable — perhaps highly unfavorable. A RAND study suggested that the overall benefit of a substantial amount of health care was small, except in certain special cases such as eyeglass prescription. A large fraction of surgeries are unnecessary, says one critic–and by large he means large:

Stanford University urologist Thomas A. Stamey, M.D., generally regarded as the father of PSA testing, says that 90 percent of all the prostatectomies performed at the Stanford hospital over the past 5 years have been unnecessary.

Earlier post on this topic.

Addendum: According to Biotech Blog,

There’s been a shift in the past 50 years away from the doctor-centric model of healthcare to one in which patients expect, and demand, better information and control over their treatments.