When every game from Far Cry 3-6 has the same open world layout and mechanics, surprise! It’s pretty hard to diversify what kind of story you wish to tell. Every single one of those games is about taking down some big bad guy and clearing all his outposts.
Far Cry 1 & 2 can actually tell unique stories since they don’t follow the same formula.
It really goes to show that enemy AI, level design, and basic mechanics all contribute significantly to video game story-telling.