I would bet money that at some point in the next 2-5 years Ubuntu will fork significant parts, if not the entirety, of Gnome...
The replacing of Gnome has already begun. They replaced Gnome Shell with Unity and GDM with LightDM. They're using Qt more often now as well (I believe Ubuntu One is Qt and I know that Unity2D is too), so it seems that perhaps GTK+ will be next.
The replacing of Gnome has already begun. They replaced Gnome Shell with Unity and GDM with LightDM. They're using Qt more often now as well (I believe Ubuntu One is Qt and I know that Unity2D is too), so it seems that perhaps GTK+ will be next.