We all know the standard story: our economy would be more dynamic if only the government would get out of the way. The economist Mariana Mazzucato says we’ve got that story backward. She argues that the government, by funding so much early-stage research, is hugely responsible for big successes in tech, pharma, energy, and more. But the government also does a terrible job in claiming credit — and, more important, getting a return on its investment.