A few more Data Point, The total online population in China is more than online population of US, Canada and Whole of EU combined. And while US, Canada and EU are separated by 10+ time zone, China is in one time zone, the peak traffic of anything that gets small traction in China is likely to be 10x if not a lot higher.

The average salary of an entry level Ruby on Rails Dev in China is under 24K USD.

And while everything is cheap in China, for whatever strange reason their Cloud Compute Resources and Bandwidth are 2x of even Amazon in Hong Kong or Australia ( Some of the most expensive instances in AWS ).

And you get the idea why pretty no one outside of High Salaries Region, ( US, UK, Germany, France ) are using Ruby Rails. Sometimes the equation or selling point just doesn't fit.