The reason Carlyle called it the dismal science is because so many classical economists were abolitionists, and Carlyle favored the institution of slavery.

I agree that counterfactuals are almost impossible to know in economics, but if predictions on one side repeatedly turn out wrong, then that side is probably wrong.

You can find innumerable doomsayers that predicted hyperinflation, and a loss of faith in the dollar and bonds. All of those people were completely wrong, and in fact the dollar strengthened, yields plummeted, and consumer prices were stable.