In Microsoft's case, there is an entire world of software that only runs on Windows. There are a lot of circumstances where businesses and users simply don't have a choice to run an operating system other than Windows because so much of the software world is built around it.

There software that runs only on macOS, but nowhere near the extent of Windows. The overwhelming majority of people using a Mac have made a decision to use an Apple product. For most Windows users, this was never a choice.