Of course it hasn't. There wouldn't be a Fedora anymore after that ;)
You just seemed to discard the idea a bit too quickly for my taste.
And I wanted to point out that desktops - or at least GNOME - have been looking at building their own distro. If you look at https://live.gnome.org/PortabilityMatrix and its history over time you can clearly see that the requirements for the underlying platform have been increasing.
And from my personal experience in talking with other GNOME developers, I would say that it's certainly been a desire of us GNOME community for a while now to define a platform and not to be "just" a desktop on top of some platform.