Considering Raskin's ideas about user interaction as "out there" is a matter of perspective. Touch screen interfaces that are now common today were once considered "out there". His love affair with the Canon Cat wasn't just a personal obsession. He made (what I considered to be) a group of well reasoned arguments about why it was so good based on the concepts it brought into reality. Off the top of my head I can recall automatic file saving (with no consideration to the file system) being one such argument. This feature will be shipping in the next release of OS X (Lion). If Raskin's ideas in the Humane Interface were "out there", then I take that phrase to be synonymous with "avant garde".
The zoom UI he talks about in another chapter (and what the OS X app Raskin has attempted to implement) seems like a strong candidate for a general data exploration and discovery UI. What he put forth in the book was conceptual, and no one has yet made a commercially or critically appealing implementation. That doesn't mean it won't happen. It just mean it hasn't happened.