I don't think that this observation is necessary true. Many economists have done numerous hands-on research that is now applicable on daily basis in the derivatives market (Scholes-Merton), Risk-management (Markowitz), Monetary policy (Friedman, Bernanke himself) etc...Not to forget about the main philosophical currents (keynes, smith, hayek) that keep on alternating and altercating every generation or so, and in different regions around the world.
Now you may rightfully suggest that some theories were discredited by current and past financial crises, corporate collapses and variant events, but this is the whole purpose of economics as a lively social science. Trial and error.
Thinking of it, with all the empirical testing and observations involved in economics, in addition to the heavy Math, one may question why is Economics considered a Social Science? But again, it does deal with Society afterall. :hmm: