what is the purpose of life universally?
survival and long-term maximal happiness.
there are two forms of greed; one is rational on an individual level, the other is not rational on an individual level.
the first form of greed is rational to individuals who can never be happy; they are only happiest in pursing more, and this is their sickness.
the second form of greed is irrational; it is arguably human nature. it is the simple enticement of more, even to truly happy people and its presence or absence in the person is dependent on circumstance, not personality in contrast to the first type.
so even when people have achieved maximal long-term happiness, and therefore the universal purpose of life alongside survival, unless they are acutely aware and accepting of the ruin that will follow from their actions, or live in a culture with values or constraints against greed, many will choose more if they can, or this second type of greed.
but insodoing they will ruin themselves.
you can't be bored of the sort of happiness I am talking about in this second instance; I am talking about where humans really are happy and where greed ruins this and they themselves wish they could back to how things were.
in this instance greed is obviously bad, and is followed by regret.
but this type of greed is on the decline because fewer and fewer people are experiencing or have experienced the type of happiness I am talking about.
on the other hand the first type of greed, which is like a personality flaw, is on the ascent and is like a drug addict's approach to happiness. such individuals have never experienced real happiness, and may never know it either due to lack of such experience in the world itself or personality, and so try to fill their lives with short-term 'hits' to an effort to achieve this maximal long-term happiness which all humans seek but whose efforts are ultimately futile and the greed-like behaviour is a testament to their basic and long-term dissatisfaction and fail.