“Most academics are really reluctant to take part in the public dialog, because the public dialog requires you to have an opinion about things you can’t really be sure about,” says Mr. Rajan. “They fear talking about things where everything is not neatly nailed in a model. They stay away and let the charlatans occupy the high ground.”
I think this is too nice. Economists do offer opinions about things you can't really be sure about, they just don't usually offer ones which deviate from an Econ 101 framework. Those things aren't "known," they're just easy.
To most people, academic economics is indistinguishable from Larry Kudlow.