Linux will never work on the desktop because it is made FOR neckbeards by neckbeards.
It is a community driven effort, which means the community pushes its development and design. Who do you see using the linux desktop? The exact type of people who design and develop it. Power users and developers.
They are a stubborn bunch. Even if Unity/Gnome 3/etc were more usable desktops, the majority of users would hate it. Because something like a newbie usable desktop just doesn't fit who's designing the desktop.
Something else will have to shove it into the wider market where it can be judged by those standards, not by what set of power user keyboard short cuts it supports.