XFree86 worked fine for me since 1994. I sometimes had problems when exiting a video game like Doom or Quake. SVGAlib would give problems but that wasn't X.
It would help if you did not give easily verifiable facts to reveal the inaccuracy of your recall. You may have been using Doom in 1994 but you certainly were not using Quake. If this is an accurate memory, what year is it from?
I installed Linux on my PC in September 1994 at the start of my sophomore year of college. I remember playing Doom during that school year from Sept 1994 to May 1995.
The Quake Wiki says Qtest was released Feb 24, 1996 and I remember playing that the week it was released.
I always felt that X11 on Linux was just as stable as X11 on SunOS, Solaris, Ultrix, HP-UX, IRIX, and AIX.
Yep, my point was my experience in 1999 with XFree86 was with Linux, which was less stable than today per se, before that I only used Xsgi on SGI Workstations, which was proprietary and was already HW accelerated.
XFree86 on Linux wasn't very stable in 1999 (although it was more than usable, more than Wayland is today).
X11 on IRIX in 1999 was pretty stable.
Parent said X, not specifically XFree86.
also something to consider: how many people were working on Xfree86 in 1999 and how many people are working on Wayland in 2023?
What was the state of the technology, tools, documentation, availability of specs, reverse engineering etc. back then?
AFAIK nobody was being paid by major tech companies (RH, just to name one) to work on free software in 1999.