I think it is a nature of a person because each person has their own percentage greediness and I think those who has a high percentage of greed will always get addicted in gambling, not just in gambling but also that involves money. Well, we are the one's who will help ourselves and we are also the one's who will help ourselves so we can control being greedy.
Everyone is greedy by nature. Even if you think you are not, you are still greedy. The fact that everyone wants to have better life means they are greedy, it is in our nature and there is nothing that could stop it. The only thing is to control it and dont let it control you therefore you wont lose yourself when you are gambling
Being greedy is not a big sin in real life, but where we are showing it, is more important. When we are gambling with greedy intentions, we will never find what we are actually looking for. When we are gambling with "don't care mindset", probably will be getting chances to make decent outcome from it.
I mean to say to control greedy we need to cheat ourselves. We need to be behave like we are not actually aiming for big profits, even intentionally we are having that mindset. Over practice, I believe this way we can overcome greedy mindset.