Or FreeBSD, or DragonflyBSD? Because part of the nature of software is that you get the most out of it when you're using what everyone else is using, and doing much the same thing as they're doing, so that the costs of figuring out how to do a given thing can be paid once and documented for everybody else to copy.
That counts whether you're using Windows or choosing to use something else - you'll never hear someone suggesting that you run Apache on Windows, as IIS is standard and what everybody else uses.