At no point I have stated that Keith has stopped working on X.
I only pointed out an article which documents (some of) Keith's opinion on improvements brought by Wayland.
There's one thing you must understand about open source: you can't force others to do your bidding. Nobody can declare X or W to be the future and kill the other.
Open source in general, has never been a democracy but a "do"-acracry: those who do the work decide and the others are left only with the choice of using what has been done by those who did it. All you can do is do the work and see who chooses to use it.
Like everything else, X and Wayland will continue to work as long as enough people are willing to the put in work to make it work. No more, no less.
People will be forced to change from X to Wayland only and if the people who are currently doing the work required to put together X based Linux desktops decide they don't want to do it any more and nobody replaces them.
X's network transparency will continue to work as long as XWayland is kept up to date and as long as the toolkits keep an X backend and the applications take care not to break.
That said, looking at statements made by people doing said work, it looks likely that in the not so far future, you won't be able to run the latest version of Gnome (maybe even KDE) on top of an X display server.
On the other hand, XWayland will probably be kept up to date forever, as toolkits older than GTK3 and Qt5 probably will never get native Wayland backends.
And removal of X backends from other toolkits is something in a very distant and hazy future.
Finally, Daniel has always qualified what he meant by "network transparency is broken".
It has been broken by countless application writers, who only care and test about their applications in a local environment, where the SHM extension gives them immense bandwidth to communicate with the server and the latency is measured in few micro-seconds.
They've, unintentionally but increasingly, made the applications perform worse and worse in limited bandwidth/latency environments.
And they (application writers) have no intention in doubling back.
And this the second time this happens, by the way. Before Xrender, applications were also on the way of pushing so much data to render anti-aliased forms, that using them over the networks of a decade ago was also problematic.
So, heed Daniel's words: X network transparency is broken.
Your ability to use it with the latest applications is decreasing and there isn't anything the X or Wayland developers can do about it.
Because, again, you can't force the application developers to make sure it does work well over the network.
And this is why Wayland does not support network transparency: it adds a lot of complexity and brings no benefit, because most application developers are not willing to make sure the applications work well.