I think (but am not sure) that WSL was a consolation prize of the cancelled Project Astoria, the initiative from the dying days of Windows Phone to support runn

I think (but am not sure) that WSL was a consolation prize of the cancelled Project Astoria, the initiative from the dying days of Windows Phone to support running Android apps on Windows. Implementing this with virtualisation would have been more painful and less practical on the smartphones of the day.