The UNIX Haters Handbook was funny at the time but doesn't make much sense these days unless you understand all the rival hacker groups and cultures that were largely eventually unified under "Free Software" and, later, "Open Source". Even the LISPers have come in from the cold!

Much of this criticism of X was prescient for things to come. Autotools, dependency problems, modularity issues, compatibility, "DLL-hell", etc. Many of these problems don't have solutions today that are orders of magnitude better than then.

On the other hand, one thing that's really holding X back, especially on handhelds, is 'Myth: X is "Device Independent"'.

If the difference between a 75dpi screen and a 100dpi workstation screen was too much, today's "retina" displays really struggle to run a usable X. You're heavily reliant on the toolkits (Qt, GTK, etc) to scale things for you and they mostly understand about font scaling but not about widget scaling.

Lots of distributions that might want to use it, for example Maemo Leste, Ubuntu Touch or Gemian, are having to do a lot of UI work and hand-pick applications for "porting" to the screens and input devices (touch) that they want to use them on.

This means that Linux-on-the-smartphone is not yet in any position to give Android or iOS a run for it's money because it really struggles to effectively leverage its existing app ecosystem.

Even ignoring security models, X struggles to provide even a compelling visual of a vision for handheld devices.

Don't even mention Wayland: that has other economic incentives that are not yet properly aligned for widespread success (including X's app ecosystem ones).