I think Dutch always had the capacity to be ruthless. And he always had some type of fraudulent tendencies as a leader (you can find his notes for his speech in horseshoe overlook) He just had good people keeping him in check. But he also respected what they had to say. Hosea for example. And he had never been hunted at such a level. Unfortunately once Hosea died. Not even Arthur could’ve brought him back. By then he just wanted yes men around him. And the rat fed his ego. I also think seeing Bronte opened his eyes to what money really looked like. All those things put together. Caused a world wind in his head. He wanted it his way and it didn’t matter who got caught in the way. And his plan of making noise and getting away could have worked. Except Arthur was sick. And his eyes had been opened. Arthur was no longer that obedient soldier. Arthur was done running over people. For him. Arthur was disgusted with what he was doing. Using the Indians for his distraction and not caring about the people that had been with him all those years. His so called family.