I work on the open-sourced Jedi Academy game engine, which is based on id tech 3. It has special logic to specifically adjust the gamma of the physical monitor during launch, then restore it upon exit.
This is why when these older games crashed on your PC, the monitor would look all washed out due to the manual gamma adjustments the game made that didn't get restored.
Nice! I remember being an early Nvidia adopter (RIVA 128, TNT) when all of my fellow LAN party buddies were Voodoo users, and I had to download a custom opengl32.dll which actually adjusted the gamma into tolerable levels so you could see what was going on in Quake.
This is why when these older games crashed on your PC, the monitor would look all washed out due to the manual gamma adjustments the game made that didn't get restored.