No, Windows had an Unix subsystem since forever, and WSL helps switchers more than ever actually.
And who in the hell ever developed for it anyway? That was a niche, forgotten product if there ever was one.
edit: maybe you should keep up with stuff more if you're going to defend it so much, it was deprecated like 7 years ago
The subsystem that was made just to claim POSIX compatibility was the subsystem that preceded Interix. Interix was developed outwith Microsoft, and replaced the old POSIX subsystem. It was Windows NT's second POSIX subsystem, and it very much is not just a sop for the sake of checking a requirements checkbox.
It's a fairly usable POSIX environment, with a large toolset, proper terminal emulations, pseudo-terminals, interoperability with non-POSIX processes including visibility with (an enhanced) ps and the ability to send signals to Win32 processes, an actual init and inetd, and an X server.
Stephen Walli has stated that it started as a fork of 4.4BSD-Lite.
Could you elaborate on how you run GUI apps? Is it through some Xorg compiled for Windows? Can you use hardware-assisted OpenGL from WSL?
So I'm wondering how much of the software requires 'Linux' per se or rather just relies on a GNUserspace such as Ubuntu.
It might be an interesting test case of WSL compatibility for Canonical/MS programmers to get this working. (although wasn't MS working on some sort of iOS bridge for WP10, in the case of Darwin-based programs?)