A little more than a decade ago, Founders Fund, a venture-capital firm run by the entrepreneur, investor, and political gadfly Peter Thiel, issued a proclamation called “What Happened to the Future?” As an investment thesis, it was underwhelming—it advanced biotechnology, energy, and the Internet as smart bets—but it was received as something of a spiritual treatise. Thiel was best known for his early investment in Facebook, but he believed that the nation had become sluggish. We might have been...