This is the decade America's common culture died. Cultural taste, affinity, and identity is shattered into a thousand distinct shards. This “tribalization” has become an obsession among social elites, whose economic model for maintaining their global dominance has been thrown into doubt. But only now are the fuller consequences of the rise of the multiculture rearing their ugly heads. As manufactured mainstream fare fades, Americans are right to begin to wonder whether any popular culture as we know it, a vibrant social sphere full of entertainers and highly engaged audiences, is going to replace what is lost. The same digital technology that empowered us to consume what we wanted, when we wanted it, is now sharply discouraging us from producing what we want, even at times and places of our choosing. The world of digital entertainment and social media is increasingly suppressing both popular culture and elite culture, each of which depends on giving people incentives to pour their lives into art, media, music, film, and the news of the day. Whether it’s injecting creative works into the market, opinions into the maelstrom of the online discourse, or corrective lectures into raging debates, the potential payoff for all these sorts of activities is plummeting. The culprit is not simply digital tech’s propensity to glut markets until demand collapses. In our era when just about anyone can write, record, produce, and release a single, a movie,...