If you go back 5 years, everyone was using Quake 3 Arena as the benchmark. ATI got in some hot water because if you renamed quake3.exe to quack3.exe, your FPS would drop by 15%, because they were silently reducing quality to juice their benchmark numbers.
5 or 50? I'd say 5 years ago it was already Witcher 3, Cyberpunk 2077, GTA 5, etc.
Apparently people did this with the DirectX "3D Tunnel" demo as well[1] back over 20 years ago.
Also there was one "that checked if you were printing a specific string used by a popular benchmark program. If so, then it only drew the string a quarter of the time and merely returned without doing anything the other three quarters of the time".
[1]: https://devblogs.microsoft.com/oldnewthing/20040305-00/?p=40...