They do have Mark Russinovich of colossal SysInternals fame as Azure CTO though.
I'm not familiar with MacOS 9 interfaces, but there are so many implementations of Unix out there (including WSL, Cygwin, Linux, BSD, and another dozen independent implementations) because the Unix interface was, on purpose, very simple. That is, in part, what allows Fuchsia and Darwin to be feasible.
Windows, on the other hand, is not. It has thousands of system calls which aren't really layered in any way. Wine and ReactOS have been at it for over a decade each and they still have "not yet implemented" system calls.
Microsoft has the "reference implementation" to compare with, but the amount of work is enormous even for Microsoft.
Than I would be happy. Well, obviously this is not going to happen but I would have been nice. :)
I have big hopes for Google Fuchsia
On macOS, video card drivers are userspace, in fact, every driver (kext) is userspace
https://www.windowslatest.com/2018/09/29/windows-core-os-rum...
I'm thinking back across years worth of recruiter spam and Microsoft would be the only major company that's not represented.