I never understood how people think running games at low or medium is even remotely decent
Seriously, cough up the loving money for a good computer/gpu and play games how they were actually meant to be played.
I guess it depends who you are.
Some people can't afford better computers, own laptops, or don't have the money / means / knowledge to replace hardware in their desktop. If its a case of playing the game or not, people will choose to play.
I personally find medium pretty fine for games. Some games have really strong settings, for example low textures in Garrys Mod make graphics on props become borderline incomprehensible blobs. Yet in other games it'll just make textures slightly rougher or remove a bit of smoothness. There is no one definition of what low settings are in a game.