At the behest of Rockstar Games, Valve has removed the original Grand Theft Auto trilogy from Steam, games no longer for sale.
Rockstar apologizes for GTA Trilogy issues, makes the old versions of GTA available again
Rockstar's Removal of Classic GTA Games From Steam Sets a Bad Precedent
Grand Theft Auto: The Trilogy – The Definitive Edition - Wikipedia
GTA Trilogy Is Back on the the Rockstar Games Launcher - IGN
Rockstar's Removal of Classic GTA Games From Steam Sets a Bad Precedent
Grand Theft Auto The Trilogy: The Definitive Edition - Nintendo Switch [Digital]
Rockstar Games apologizes for Grand Theft Auto: The Trilogy - The Definitive Edition technical issues, announces update plans - Gematsu
Has Grand Theft Auto: The Trilogy - The Definitive Edition On Switch Improved Since Launch?
GTA Trilogy Fans Use Steam Reviews To Encourage Sales Before Delisting
The infamous GTA Trilogy is now on Steam, and it's coming to Epic Games Store
Classic GTA trilogy removed from Steam, still up on PS4