From Arnold Kling:
5. Certified macroeconomists were taken by surprise by what has happened. A lot of people saw the boulder of the housing bubble ready to roll down the mountain. Hardly anybody foresaw the financial avalanche that would ensue.
6. Certified macroeconomists were badly polarized in the early 1970's, with Chicago types essentially denying the idea of involuntary unemployment and the MIT types clinging to macroeconometric models. By the late 1970's, the arguments were over. The models had all sorts of problems, and everybody gave up on them, although people had different reasons for doing so. Methodologically, everyone agreed to work on irrelevant math probems, and substantively everyone agreed that reasonably stable money growth would lead to a reasonably stable economy.
7. We had reasonably stable money growth under Greenspan and Bernanke (at least that is what most people would have said at the time), but look what happened.
8. So now, it's back to the early 1970's, with Chicago denying reality and MIT back to thinking in terms of macroeconometric models.
History may not repeat itself, but it stutters like hell.