U.S. workers are more productive than ever -- but corporate productivity, as measured by return on assets, is at a quarter of the levels seen in 1965. That's an indictment of our current business models, writes Margaret Heffernan, and a sign that companies need to quit working hard and start working smart. "By anyone's measure, this represents failure," Heffernan writes. "It's a number that should shock and provoke every business leader and business school. We are doing less with more -- at a time when we need to be doing exactly the opposite."