Most workers suffer serious consequences when they mess up on their jobs. Custodians get fired if the toilet is not clean. Dishwashers lose their job when they break too many dishes, but not all workers are held accountable for the quality of their work.
At the top of the list of people who need not be competent to keep their job are economists. Unlike workers in most occupations, when large groups of economists mess up they can count on the media covering up their mistakes and insisting it was just impossible to understand what was going on.