If you were right this wouldn’t be a store page:

https://www.microsoft.com/en-us/store/b/windows

Windows 10 Home starts at $130, Pro is $200, and the business licenses start at $300. Given how much of Windows market share comes from business use, it’d be surprising they weren’t making a lot of money there. Since they’re a public company it’s easy to confirm that, yes, selling the most popular operating system in the world is profitable:

https://www.microsoft.com/en-us/Investor/earnings/FY-2020-Q2...