Defunct consultant!

John Maynard Keynes said this about economic policy making between the wars

"The ideas of economists and political philosophers, both when they are right and when they are wrong, are more powerful than is commonly understood. Indeed the world is ruled by little else. Practical men, who believe themselves to be quite exempt from any intellectual influence, are usually the slaves of some defunct economist."

It could easily be re-phrased as...

"The ideas of consultants and experts, both when they are right and when they are wrong, are more powerful than is commonly understood. Indeed the world is ruled by little else. Politicians and bureaucrats, who believe themselves to be quite exempt from any intellectual influence, are usually the slaves of some defunct consultant or self-proclaimed development expert."

... to describe the state of administration in many important sectors.