[user5994461]

Xiaomi are not available for sale outside of China. (Well, not without jumping through hoops and weird resellers).

They have zero name recognition worldwide and the platform is fitted to the china market. There are some minor localisation and translation work to go global. Most important of all: They lack the brand recognition (westerner are very sensitive to branding and associate china with cheap shit).

Outside of that, they do S6/iphone7 equivalents for half the price.

They could blow away every single android manufacturers single handedly if they went global.