Also known as, you don't know technically anything about Windows.
There is a very big difference between supporting UNIX, and Linux kernel syscalls ABI on top of pico processes, the technology from Drawbridge kernel taken out from Microsoft Research, which incidentally is also used to port MS SQL Server into GNU/Linux.
As for the rest I could provide examples of how the BSDs and Solaris failed in similar attempts to clone Linux syscalls table, despite being UNIX, before Microsoft's attempt, but who cares?
> As for the rest I could provide examples of how the BSDs and Solaris failed in similar attempts to clone Linux syscalls table, despite being UNIX, before Microsoft's attempt, but who cares?
the BSD approach is still supported and part of FreeBSD, so presumably someone cares about that
yes, that's why the attempt to provide a Linux subsystem on top of the NT kernel (WSL1) was so successful they abandoned the approach entirely
WSL2 runs the full Linux kernel in a sidecar VM