You’re not just king of the pile of shit your kingdom sits on. You’re king of the people. You have an army at your disposal in a world where everyone is fighting over the very little resources that are left to survive. You are old and also have a chronic medical condition that makes it difficult for you to survive on your own. Why wouldn’t you want to be the guy at the top, with plenty of food and water and safety? Are you saying you want to be Max?

And that’s just the surface level reason. Think about how you could shape the future if you were the one with power. I don’t think anyone who wants to be Immortan Joe or whoever ran Barter Town just to go and do things the exact same way. They probably think they could rebuild society.