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.