[midnightclubbed]

id tech is probably the last engine that used a signature game to showcase the engine to licensees. The business model of idTech, Unreal Engine, and Crytech used to be 'make amazing looking game that sells the engine to licensees'. The problem with that model was you got a cut of the game code for whatever the 'amazing looking' game was and told to figure it out. If you wanted to make a Gears of War clone then Unreal Engine 3 was perfect... for every other game genre you had to rewrite and implement huge chunks of code.

Unreal Engine managed to evolve and expand the engine to the point where it is somewhat game agnostic, crytech became lumberyard under Amazon and died, idTech became the engine solely for iD games (ie the same business model as every other game or publisher custom engine).

iD tech's rendering pipeline is focussed on the one AA game iD are publishing that year and making that one game run efficiently and beautifully on mid-high end PC and current consoles. UE5 is focussed on providing tools for anyone to (relatively) easily make good looking games and applications that can be published to a wide range of devices.