Neither pricing nor the economy fully explains why Apple's suddenly doing so poorly in China and not in the US or EU. They're triggers certainly, but not the root cause. There's one keystone here-- WeChat.<p>In the US and EU, Apple has people locked into their ecosystem. That doesn't apply to China. WeChat is their alpha and their omega. They use it not only for chatting, as you might expect from its name-- WeChat is in many ways their _entire operating system_.<p>You pay your utility bills with WeChat, it's your social network, map app, phone app for VOIP, video calls, you access local services, your banking, payments like Venmo, your healthcare, read the news, buy stuff from online stores, EVERYTHING is in WeChat.<p>And WeChat is cross-platform.