Rosenthal: X Window System At 40

David Rosenthal looks
back at 40 years of the X Window System:

A major reason for Sun's early success was that they in effect
open-sourced the Network File System. X11 was open source under the
MIT license. I, and some of the other Sun engineers, understood
that NeWS could not displace X11 as the Unix standard window system
without being equally open source. But Sun's management looked at
NeWS and saw superior technology, an extension of the PostScript
that Adobe was selling, and couldn't bring themselves to give it
away.