Keynes was not an innovator and champion of new methods of managing economic affairs. His contribution consisted rather in providing an apparent justification for the policies which were popular with those in power in spite of the fact that all economists viewed them as disastrous. His achievement was a rationalization of the policies already practiced. He was not a “Revolutionary,” as some of his adepts called him. The “Keynesian revolution” took place long before Keynes approved of it and fabricated a pseudo-scientific justification for it. What he really did was to write an apology for the prevailing policies of governments.
Ludwig von Mises, ‘Lord Keynes and Say’s Law’, in Planning for Freedom, and other essays and addresses, South Holland, Illinois, 1952, p. 69