1. Because it's not open source. This isn't purely an ideological thing, but that I tend to run into obscure bugs, so being able to look through the source and submit a patch is incredibly useful to me.
2. Because what I want doesn't exist. Windows NT has excellent technical foundations, but I really don't like using Win32 or any of the Windows shell stuff, but there's no way for regular consumers to use Windows NT without Win32. (WSL exists, but that still requires a full Windows installation)
3. The ecosystem. Linux tends to have much better support than Windows for the types of software that I use, and a hypothetical GNU/NT hybrid would have even worse than both Windows and Linux.
2. Because what I want doesn't exist. Windows NT has excellent technical foundations, but I really don't like using Win32 or any of the Windows shell stuff, but there's no way for regular consumers to use Windows NT without Win32. (WSL exists, but that still requires a full Windows installation)
3. The ecosystem. Linux tends to have much better support than Windows for the types of software that I use, and a hypothetical GNU/NT hybrid would have even worse than both Windows and Linux.