Humans want more even if he has many things already. The hunger of having much more will not stop them from making more sources of income. They want to become the richest person in the world so they will create more and more sources that can produce them wealth. I don't know if that is competition among the richest people but all people, not just rich people but also poor people want to be wealthy. The other things that can push these people are greed. They want to get more and more without thinking that it is enough for them. They want to eat a bigger portion than others.
Yes, you are right there is a large number of people who are greedy and their greed has no end. there is a very small number of people who pay gratitude and feel satisfied for what they have. greed is only based on the thoughts of having more. It goes out of limits when we never teach ourselves to be grateful. The perfect example of a greed which never ended has in the minds of our government. they find a chance to make some corruption they did it very confidently and they never regret it. Although they have already more than enough for them and their children and their grandchildren. But their taste of having more has no expiry. And there are a lot of examples of those people who had more than enough but their end was something which is learnable. I think it is best to have according to our needs and more according to our desires. Because once we thought to collect then I think we will push ourselves in endless and meaningless efforts.