Vscode does not use react specifically for the licensing reason. I don’t know if they do now but when I was at MS this was the case. I know many teams at MS who evaluated react and lawyers strictly advised to stay away from it. I hear things have changed a bit, but you’ll never see Office and Windows use it.
That’s not “Office uses React”, it’s a “collection of robust components designed to make it quick and simple for you to create web experiences using the Office Design Language.”
Very limited “use”; mostly just enabling external developers to interface using React to their existing tools (that are not using React). If the Armageddon should come, and Microsoft is to enter a legal patent dispute/battle, stopping this React “use” is a no-op for Microsoft.