Over the last 20 years, Silicon Valley has benefited from a once-in-a-lifetime alignment of advantages. American primacy, the ubiquity of cheap capital, the arrival of the smartphone (among other widely adopted tech innovations), and, perhaps most significantly, a benign regulatory environment have all conspired to create a historic concentration of wealth and power. The titans of the Valley and their heirs have been free to roam far ahead of lawmakers, watchdogs, and tax codes.