Eric S. Raymond wrote the same erotic fanfic a few years back just before his blog went kaputski (http://esr.ibiblio.org/?p=8764). It won't happen, because the NT kernel is a massive improvement in architecture over Linux or any conventional Unix—and Microsoft has proven, with WSL1 and 2, that they can achieve Linux compatibility while still basing everything on the NT kernel. Switching the Windows ecosystem to the Linux kernel is harder, because Hyrum's Law applies and some Windows binaries operate by using NT syscalls directly, bypassing msvcrt and Win32. And Windows has something Linux doesn't have, and it would take enormous effort for it to get: a sane driver model. It is possible to ship a device with a binary Windows driver and have it Just Work, even on later versions of Windows; this is just not possible under Linux.

The future for Microsoft is doubling down on "security" by making the PC as a platform more restricted: requiring a signed boot path mandatory from power on down through the application level code. They can convince OEMs that this is necessary for compliance with internet safety laws in certain countries, some of which require safety checks (like age verification) even on end-user equipment. It looks to me like some of their moves point in this direction: Windows 11 requires TPM 2.0 because the plan is for Windows 12 to be a completely closed platform. Xbox is being phased out because the thing that distinguishes an Xbox from a cut-down PC—the locked-down nature of the platform—is something Microsoft intends to bring to all PCs with Pluton.