The entire passage of Keynes gives a different sense:

Ricardo conquered England as completely as the Holy Inquisition conquered Spain. Not 
only was his theory accepted by the city, by statesmen and by the academic world. 
But controversy ceased; the other point of view completely disappeared; it ceased to 
be discussed. The great puzzle of effective demand with which Malthus had wrestled 
vanished from economic literature.

Keynes does not seem to be bemoaning the absence of heterodox views, but a much 
narrower question -- the emphasis on aggregate demand.

Michael Perelman