But the Keynesian macro models similarly have little predictive power. They've failed most of the modern tests which actually distinguish them from monetarism.

But the Keynesian macro models similarly have little predictive power. They've failed most of the modern tests which actually distinguish them from monetarism. (There have been several "tests" of Keynesian thinking where Keynesian predictions agree with monetarist predictions, but such tests can't distinguish between the two theories.) Most of the modern shift in economic thinking is based more on fashion than on new information. See, e.g., Scott Sumner on the topic: http://econlog.econlib.org/archives/2014/05/when_ideologies.html http://econlog.econlib.org/archives/2014/05/when_ideologies.... http://econlog.econlib.org/archives/2015/03/ways_of_thinkin.html http://econlog.econlib.org/archives/2015/03/ways_of_thinkin....