It’s been about a decade since a new generation of mobile apps brought online dating out of the shadows and onto our phones. They turned swiping — right or left — into a kind of romantic roulette. Dating apps have become the most popular way for couples to connect, but they’re also a multibillion-dollar industry that relies on keeping users hooked. Marketplace’s Meghan McCarty Carino spoke with Sangeeta Singh-Kurtz, co-host of the podcast “Land of the Giants: Dating Games,” a collaboration between The Cut, The Verge and Vox Media, about how dating apps have been “gamified.”