It depends what you mean by "it". FUSE clearly doesn't give you every feature in plan9, and in fact you can't have that without giving up the current Linux syscall API completely and replacing it with something vastly simpler that leaves a lot more to be done in user space. That's not something that Linux is going to do by default, seeing as they have a backward compatibility guarantee for existing software. Which is totally OK as far as it goes; the two systems just have different underlying goals.

You're frustrating me. You replied to me saying "it's basically FUSE" and then after I replied to you, you come back and say, "it's not really FUSE."