how and why does steinbeck creates a power hierarchy on the ranch?

Nobody on the ranch wants to get fired. Work is very hard to come by. So, the power structure creates external conflicts that affect each character. You have the boss at the top. He only cares about work getting done. Slim has power and the respect of the men. He is the crew boss. There is a sense of fairness about him. Curly, the boss's son, has a major small guy complex. He abuses his power as the boss's son to stoke his own fragile ego. This creates much tension among the workers. Candy is the old man near the bottom of the hierarchy. He simply exists trying to hold on to the menial job he has. A crook is almost at the very bottom. Isolated for his skin colour, he has no power. Curly's wife doesn't even get a name. She is relegated to ghost status lurking through the ranch, trying to both "look" for and dodge her abusive husband.