I think at least part of the problem was the hardware required to run a more complete installation where you'd start to see the benefits of the approach. As the paper outlines, a Plan 9 network needed at least a CPU server, file server and one or more terminals, plus possibly an authentication server (the CPU server might have been able to do this too). I seem to remember that the installation instructions assumed you'd have this kind of hardware available too, so getting a working system was quite an investment.
The file server was somewhat specialised too: the Plan 9 one used an optical WORM jukebox to provide its long-term storage. If you didn't have one of those you could simulate it with disk storage, but there's a cost trade off there.
Without this investment in hardware it was like trying to understand how NFS or web infrastructure works with only a single machine to work with.
In some ways it's similar to the obstacles that hobbyists face investigating the Hadoop ecosystem today: the hardware required to build a realistic installation on which to experiment is quite costly. With Hadoop you can use virtual machines and/or cloud hosting to try things out. When Plan 9 came out you didn't have that option so you needed to assemble physical hardware yourself.
> As the paper outlines, a Plan 9 network needed at least a CPU server, file server and one or more terminals, plus possibly an authentication server (the CPU server might have been able to do this too).
... which can just be run on the same machine.
> Without this investment in hardware it was like trying to understand how NFS or web infrastructure works with only a single machine to work with.
Network transparency is an important feature, but not the only one. You are saying running X makes no sense because your X server and client are on the same machine.
The file server was somewhat specialised too: the Plan 9 one used an optical WORM jukebox to provide its long-term storage. If you didn't have one of those you could simulate it with disk storage, but there's a cost trade off there.
Without this investment in hardware it was like trying to understand how NFS or web infrastructure works with only a single machine to work with.
In some ways it's similar to the obstacles that hobbyists face investigating the Hadoop ecosystem today: the hardware required to build a realistic installation on which to experiment is quite costly. With Hadoop you can use virtual machines and/or cloud hosting to try things out. When Plan 9 came out you didn't have that option so you needed to assemble physical hardware yourself.