Large governments have access to Windows source code. https://www.microsoft.com/en-us/securityengineering/gsp https://www.microsoft.com/en-us/securityengineeri

Large governments have access to Windows source code. https://www.microsoft.com/en-us/securityengineering/gsp https://www.microsoft.com/en-us/securityengineering/gsp It's more about long-term strategy. China wants full control over their OS. They want features Microsoft would never add. They want support for their own hardware, etc.