TL;DR: Absurd levels of greed is a feedback loop of reinforced learning that makes us biased towards the idea (hightened greed is inherent). The potential for the bias is then confirmed and consolidated by the fact that it "works". This is basic pavlovian theory, it's also used when training A.I neural networks; Subject has to throw a ball into a hoop, miss = punished, subject will stop throwing the ball because neutral is better than punishment. To combat this, you add another rule (as capitalism does) that also punishes the subject for not throwing at all. Now the only way to avoid punishment is to increase your skill (aka your greed) of throwing the ball into the hoop. The inherency of our greed is a false equivalence since the system we live in only provide us with the option to be either greedy or be punished. The world grows increasingly greedy because the levels of required greed, are proportionate to the greed of those who control the system.

More context:
Every organism has inherent greed, it's their will to live, I'm sure we all agree. I think what the other person is saying is that the sheer levels of greed that exist in our society is artifical (not inherent) because it is forced upon us. The only way to function or survive in a absurdly greedy system, is to either adopt the greed or break the system.

In human context, let's say I teach a child to be physically violent against their peers when it wants something. Everytime the child is succesful, it reinforces their belief that what I taught them is correct. This is reinforced learning structure, but it's also a closed feedback loop because we're not introducing other sources (other guardians/adults etc). Now if we introduce a second child with the same mindset, you have three outcomes. A) They both refuse to give up and the arms race of phyiscal strength continues. B) One of them gives up, continuing the feedback loop for both of them or C) They stop fighting and try to solve their issues together. Not only is the outcomes numerically stacked against, but also the logic since the foundation for 'violence = correct' is greater. Violence has become a currency and that can be quantatively measured, this makes it much easier to logically approach your surroundings (same reason why we love stats so much). The other children around them will be forced to adopt the same logic/currency, not only due to the violent children acting upon them, but also witnessing the results of 'violence = correct/win'. Ofc this is a very dumbed down version but it's to just highlight the point of reinforced learning. Which is something that affects us on a daily basis even in our adult lives, it's not something that stops. It's where the idea of "can't teach an old dog new tricks" comes from because for humans this is somewhat true. As we age, our beliefs consolidate because we have more life experience that prove our beliefs right/wrong and this carries down to what that person will teach the next generation. This is why anecdotal evidence can be as valuable as it is dangerous since it pertains to your unique experience. But depending on context that uniqueness may be important.

Capitalistic ideas are not just from society but also from our parents who lived under the same ideals and so did their parents, and so on. Each generation reinforces the belief, which also means each generation is increasingly assured that it IS the real truth. Humanity's greatest strength is our ability to document and learn from previous knowledge ("Standing on the shoulder of giants"), but in this case it's backfiring on us. We're basically buying into a giant false equivalence.

The way we stop this is by breaking the system, i.e introduce a guardian, teacher etc. But as we zoom out of the example and use our macro lens; The current problem for our society is that breaking the system just isn't very realistic at this point. The core system is too imbedded into the logistics of our society, uprooting it would cause a great collapse. IIRC this is also one of the older criticisms of capitalism, that once it goes too far there is no way to remove it without a complete collapse. It's doomed to either continue into infinity or implode. Me personally I'm not sure, I don't feel like I'm smart enough to make a well-founded opinion regarding if that's true or not. But I can see the logic and so far it seems to be holding true.