In 2013, when I was a reporter for The Wall Street Journal, I flew to St. Louis to learn about the city’s budding startup scene. The city, like the rest of the U.S., was stuck in a decades-long entrepreneurial slump that had left its economy dependent on a handful of big, staid corporations — corporations that were pulling up stakes to head overseas at a rate that alarmed local leaders. (The city’s iconic brewer, Anheuser-Busch, had been sold to a Belgian conglomerate five years earlier.) But an informal coalition of local business leaders, wealthy investors and ambitious 20-somethings were trying to spark an entrepreneurial revival in the Arch City. They had launched a fund to invest in local ventures, created entrepreneurship clubs at local universities, and converted part of a massive downtown office building into an unlikely startup hub.