Chris Siebenmann over on his personal web page at the University of Toronto writes about X networking. He points out two main shortcomings preventing realization of the original vision of network transparancy. One is network speed and latency. The other is a too narrow scope for X's communication facilities.
X's network transparency was not designed as 'it will run xterm well'; originally it was to be something that should let you run almost everything remotely, providing a full environment. Even apart from the practical issues covered in Daniel Stone's slide presentation [warning for PDF], it's clear that it's been years since X could deliver a real first class environment over the network. You cannot operate with X over the network in the same way that you do locally. Trying to do so is painful and involves many things that either don't work at all or perform so badly that you don't want to use them.
Remote display protocols remain useful, but it's time to admit another way will have to be found. What's the latest word on Wayland or Mir?
Source : X's network transparency has wound up mostly being a failure
(Score: 3, Insightful) by Whoever on Saturday February 10 2018, @05:11PM
Let's not forget that the original plan was that Wayland would NOT have network transparency. It was only the outrage of Linux users that changed it.
This seems to be a weak justification for that original position, based on the fact that network transparency in X has some limitations.