Imagine opening a single app that allows you to hail a cab, pay your friends, order food, and a million other things. Just about anything you want to do online can be done within this one app. Want a manicure? Go to this app. Craving a burrito? Same app. Need a cab? Open this app. We’re essentially describing WeChat, the 12-year-old Chinese app that holds a dominant and unparalleled position in the lives of China’s 1.3 billion users. It’s arguably the biggest mobile software success on the planet. Advertisement But in recent years, a slate of new apps—especially across Asia—have...