In GTA 4, everyone farmed Hangman's NOOSE, Rockstar changed nothing (Not that I remember).
In RDR, everyone farmed Pike's Basin, Rockstar halved the rewards after a certain time.(Although you can still farm, but at a slower pace)
In GTA Online, everyone farms violent duct, the replay option gets removed(twice), and the reward was watered down to 1/3 of it's original reward.
What happened to Rockstar to make this change?