GTA V allowed you to own a dog. Sounds like a good idea but in practice, it's as useful in high-speed pursuits as your actual dog is. It was a neat idea, but Rockstar poured a tonne of effort into a feature that was relatively minor, and most players didn't use beyond the actual missions you were forced to do so.
It didn't help that every five minutes, the game reminded you about an app to train said dog, just to unlock tiny buffs to an already useless moveset. All Chop did was maybe kill one guy, all the while becoming more of a liability in a gunfight.
It came down to the fact that most players of GTA didn't go into the game with the intention of training a virtual dog. They wanted to shoot and drive and kill things. The effort required to make Chop barely worthwhile was far too much, and so the mutt ended up sitting around aimlessly for the entire time.