As a PC gamer like rob, I do feel quite saddened that games designed on PC's are never released on PC.
Sometimes though they get released later on PC and the main reason for this, by my reasoning (especially for GTA 5; a game for gamers not just to make money) the ps3 and 360 version have already been released and tbh they dont do the game justice... they are running on 7 yr old tech afterall and the tech wasn't even top range at the time. so i think what happens is they kinda have to bump up the graphics/general quality for a PC release