Not that "finally", Windows NT was designed specifically to support POSIX and OS/2 alongside Win32 apps and the first few versions actually shipped it.

Though WSL required more work than WSU or OS/2: they needed a new lightweight process model, for example. That's more serious internal work.

Eh, the WSL stuff avoids most of the NT subsystem style flexibility.

I interpreted that as sarcasm, actually.

He isn't known for being a fan of Unix.