There are many other reasons, some of which I will be going through in my talk at the next GTALUG.
Preview: There is also simple fatigue with thye Linux desktop, such as fighting a never-ending battle with its sound subsystem. PulseAudio would think that my USB microphone is also my default speaker because it has a headphone jack for monitor mode; so PA reverts to that default at every bootup. Eventually you just don't want to keep fighting that kind of crap, and in online community support forums dead ends far outnumber problem resolutions. There are quite a few other war stories built up over the years. Windows has improved markedly in stability, I have encountered zero BSODs in Windows 10. Also, there are too many wonderful programs and peripherals out there that simply will never support desktop Linux distributions that collectively haven't risen above 3% of the global installed base (
and are now at 1.85%).
Linux-the-OS is but one piece of open source software, while I interact daily far more with my apps than the OS. One can replace Linux with Windows and still run a full suite of FOSS applications, quite a few of which actually run better under Windows than they do under Linux. Video processing speed can rise significantly when Handbrake (also others) is able to exploit GPU cycles when the driver enables it. I never have to worry about that app which insists on looking like GNOME even though I'm running KDE. And while Steam supports Linux, its experience is optimised for Windows; Linux will never be a preferred gaming platform.
The Cloud is Linux.
Servers are Linux.
Mobile is Linux.
Education is Linux (Chromebooks, Raspberry Pi, etc).
Playstations and Macs are BSD-based.
I personally have no problem conceding the productivity and gaming desktop OS to Windows, we've won nearly everywhere else. And thanks to WSL, I can still run Linux off my desktop when I want it without needing to dual-boot.
Hard to speculate, but I envision that the experience of the Edge browser was a dry-run for Windows. Abandon a proprietary platform and evolve to proprietary pieces on top of an open source core. That means Windows will become Linux-based in a similar manner to ChromeOS. Developing WSL is giving MS the expertise in the shims and compatibility layers it will need if it ever goes in this direction.