On Monday, 181 chief executives of companies like JP Morgan, Apple, and Comcast took out a full-page-ad in the Wall Street Journal to announce that their group, the Business Roundtable, was redefining the “purpose of the corporation.” Their old philosophy said “corporations exist principally to serve their shareholders.” Now, the group says, they’ll do their part to create an “economy that allows each person to succeed” by balancing the interests of shareholders, customers, employees, and the community. This is good news on paper. Obviously, it’s better to have a bunch of high-minded CEOs than for our corporations to be run by people who don’t even pretend to care about their…