Linux has won on phones (Android) and on the server side. I don't think Windows Server is seriously used for anything but Exchange/AD these days, outside of hosting specialized or legacy apps.

Windows also comprehensively lost the "exclusivity" moat. Most of popular apps are now cross-platform, because they need to run on Android/iOS/macOS. So desktop Linux is often an easy addition: Slack, Discord, all the messengers, Zoom, various IDEs, etc.

So Linux indeed won to a large extent. Just not in the way people expected it.

The Linux kernel won on phones, there is hardly any GNU/Linux on a Java based userspace.

And everyone that tries to force GNU/Linux via NDK, discovers that not everything Linux is supported.

Even if you consider running on tightly locked down devices to support a monopoly a win, the adoption of the Linux kernel for Android has the same basis as it does for server adoption: people love getting the hard work of others for free. It's basically buying market share. I mean, if Microsoft also started giving away Windows for free and took a bunch of market share away, would you consider that a legitimate win for them?

Windows is still very present in the Enterprise, for many more reasons than AD/Exchange.