No one is born with greed. It develops based on environment, but there are multiple pathways that lead to what we would generally consider "greed" in colloquial language.

Society. You only have to go back 20- 30 years to see how different we were. Both parents are now forced to work, children are in the state system longer in order to become good obedient consumers. People spend most of their life working, but the elite putting further strains on the economy ( the magical ideology), and so people are taught unhappiness, and so work to buy things to distract themselves from their unhappiness which they then have to pay off. Just think we're in a system where people look forward to 4 weeks holiday a year, and Christmas day (commercialised). We are enslaved to the system. We have no time to work out why we are like this, tomorrow you could change the system for the better, simplify life, spend more time with family less time at work, but they don't want that. https://youtu.be/lm8oxC24QZc?feature=shared

I think we are a clean slate at birth except for basic reflexes, instincts.

Technically traits that resemble greed can be acquired during gestation due to the disposition of the mother/parent(eg does the mother practice any kind of discipline in her dietary behaviors while carrying the child?) We cannot forget that babies are learning and reacting to stimulation even while still in the womb. I believe dietary behaviors are likely the root influential process that can lead to other kinds of "greedy" characteristics. For example a child whos meals are often stolen by other siblings may develop a tendency to hide and hoard their food and valuables from a primal fear of them being taken. Miserliness and frugality can be perceived by others as a type of greed. Particularly, those who have accrued less resources but are more comfortable about spending, may view hoarding resources as antisocial.. Genetic expression may also play a role in how intense the instinct to "feed" manifests. However in humans, learned behavior during and after gestation eventually has more impact on a person than any instinctual predispositions, particularly since there are practically no situations where a human is not raised by another human or community. So for me the short answer is society/upbringing has a greater impact on the development of greedy behaviors, but there are instinctual factors that play a role in its manifestation as well.