Anything we do is on some level (usually on a very basic level) influenced by greed. Don't agree? Well, You should. We work because we wont more - and we don't stop when we've earned enough if we can get even more. We Have children because WE want to have children (to satisfy our urge) - not because we want to make a new person. We spend time with our loved ones, give them presents and affection because it makes US feel better...
And it's not only each and every one of us - the system is the same. The whole market economy is structured in a way that urges everybody to have more and more and more. And this type of ecenomy is clearly dominant system on the planet. But it started that way - the prehistoric man went out to kill a bear for food the first time but next time he went because he (or his wife) wanted a fur coat. And next time because the teeth of the second one weren't white enough for the necklace....
Can we - or should we - do anything about it? Can we - I guess not. Well, we can when we are full, rested and relaxed, without worries about tomorrow - than we can say 'greed is bad, let's stop it'. But when you are hungry, tired and don't know where your next meal is coming from - You just WANT - like a baby that doesn't know anything except that it wants food. And should we (setting aside that there's no real point in arguing this as we cannot)? Maybe. The greed brought us from the cave to the skyscraper - that's true, but it also brought the skyscrapers down. I think it's time we think about changeing it before it brings down everything else.