Re: Example in today's news: Unimpressed by Gnome
No, it's NOT being replaced by an extension--at least not by the Gnome team. The Gnome team decided to drop support for icons on the desktop, with NO plan to replace the functionality. So, a Gnome developer promised to write an extension.
If Gnome had announced that they were replacing the desktop-icon support (from Nautilus) with an extension to do the same thing, and not pulled the nautilus support until the extension was ready, nobody would have batted an eyelash.