I use plan9 every now and then. I do appreciate the simplicity of a true multiplexer and the related sharing / substitution of name spaces, but it's just not a daily driver. Besides, you can get similar effects from the users perspective in linux using ssh, fusemounts, and/or X11 forwarding or xpra.

Plus, machines are way more powerful and have a lot more ram and storage, and networks are way faster, than what Rob was working with at that time. That defeats a lot of the need for distribution of network resources.