so like ig developers just made assumptions
that are obselete now lol

i believe for a lot of games it's just that even the most powerful PCs at the time the games were made would struggle to run them at more than 20-30 or 60 fps

even in GTA 3/Vice City/San Andreas, stuff like car braking behaves differently depending on your FPS
lol

but if i try playing for example Rainbow Six Vegas 2 at more than 60 fps, the physics and the IA will behave weirdly
for example the character will get too much speed on slopes (and tbh i have this feeling even at 60 fps)

Half Life 2 is a counter-example (or maybe it was in advance on its time), because it is an "old" game yet it has this "physics frames" system (i forgot the actual term), it will only update physics 20 times per second, regardless of your actual FPS

the issue is just that most older games just calculate physics and/or animations for every frame, like, in a raw way, unlike modern engines which would compensate and take into account the "delta" (the time elapsed between two frames)
or will even have independent "physics/logic" frames

Ça couplé avec ma peur du jugement et du rejet
C'est horrible