Microsoft is losing Builders fast. They’re switching to MacOS and Linux. The biggest pull keeping people on Windows, outside of shear inertia, is content creation and gaming. However, even these are falling to Linux.
Without Builders, you don’t have software, and without software, you don’t have users. This is why Microsoft needs Windows Lite.
There are many alternatives to Active Directory, some even cross-platform. Microsoft basically has a monopoly in such things because those alternatives don’t work well on Windows (both OS and Server).