They seem to be arguing that, because economists missed the Great Recession, economics is a failure.

The problem is the assumption is that a severe, large event is inherently very predictable because it is severe.

The opposite often happens, though. As you say, predicting volcanic eruptions, earthquakes, suicide, violent acts are all notoriously difficult to predict, and you could make the argument that severe economic events are the same (I'm not saying this is true, only that it's an equal counterargument).