I disagree that ABC is the only school of thought that has an explanation. Almost every economic school of thought can discuss decreases in aggregate demand and aggregate supply. Not every school of thought may have theories regarding the drivers thereof, which is a feature ABC spends a lot of time on, but some do and most can assess and even build predictions for anticipation.

As an example where ABC will go off the rails, our current crisis is not one build up due to overage in inventory, a favored ideal rationale for ABC to explain the business cycle. Much more explanatory, surprisingly, is Keynesian animal spirits.