The graph would be different because the focus would be on the talents instead of the Covenants. You don’t know what people would pick, but you would know that the powers associated to that Covenant would be picked.
It’s doodoo because you’re a progression player. I’m willing to bet that the majority of the player base could clear Heroic and KSM regardless of what is picked, but they just follow the path of least resistance.
So it’s not that Covenants are super terrible for the majority, but its just mighty inconvenient for progression players.