You missed the point. This is why he talks about Plan 9. In Plan 9, everything IS a file. Including sockets, and windows, and processes. Several of these features have made their way back into linux.
I agree, but this should have been from the start, or at least from UNIX-Internet marriage. My point was little tongue-in-cheek, but I believe that during the years UNIX has got things that are not truly with their initial idea. Or little more interfaces than necessary.
/proc is an attempt to retrofit plan9 ideas back on Linux. Plan9's is far more powerful, because you can control the visibility of filesystem mounts per-process.
That does suggest the idea of implementing a FUSE filesystem that represents all clients connected to the X server (or Wayland). That could be interesting.
As far as I can understand, this was exactly the problem that Plan9 tried to fix. UNIX had started from the concept of "everything is a file", but then as new things got added, those didn't follow the philosophy. Plan9 was an attempt at a fresh start where such non-UNIXisms could be moved back to files.