> everyone in China appears to pay by mobile phone without problems using WeChat Pay and Alipay and no one seems to be locked out.

That is not true. I met people who don't have Alipay/WeChat on weekly basis. China's central bank beat those who refuse to accept cash payment with a big stick - Alibaba's Freshhema is a high profile target the central bank recently picked, there was actually a news article on that yesterday.

For me, I am more concerned about the fact that people's life could be dramatically affected if both Alipay/WeChat ban their accounts, say due to some business disputes. There is so far no regulation on this whatsoever.