

I had to dig through their annual report to find it:
Server products and cloud services revenue growth
Revenue from Server products and cloud services, including Azure and other cloud services; SQL Server, Windows Server, Visual Studio, System Center, and related Client Access Licenses (“CALs”); and Nuance and GitHub
So it includes Windows Server, but it’s way more than just that.

In the hypothetical situation Windows desktop monopoly is over, there’ll be at least some internal pressure to do so. Cost of switch (in money = work hours) might be a pain, but if they believe they’ll profit more by using some competitor that is not Windows exclusive, they’ll eventually do it.