Related: 10 Movie References In Grand Theft Auto Vice City Only True Fans Noticed Alongside GTA Online and its own fan-created content, it's certainly one reason why Grant Theft Auto V remains so popular.
A thriving mod scene can bring new eyes to a game, keeping it selling years and years past its original release date. Since PCs are open by their very nature, developers have a hard time locking any of that stuff down, and most don't try in the first place. While Grand Theft Auto is popular on both computers and consoles, the closed platforms of Microsoft and Sony make it very difficult to alter game code on a consumer device.
Of course, most of this modding takes place on PC. It's all outside of Rockstar's vision for its crime-filled universe, but that's why it's so fun. Even outside of the important legacy of the Hot Coffee incident, players have recreated old cities in new engines, flooded the world map, and added in unlicensed superhero from a certain popular cinematic universe. Modding has always been a big part of the Grand Theft Auto experience for many, as the game's huge fully realized world lends itself well to alterations of all sorts. One Grand Theft Auto V modder has seen fit to grace the game with a 'mega ramp' of his own creation.