I agree, to an extent. But it's not "our society". It's physics.
A person (singular) can grab as much as they can (and wish to) hold. An individual in good health in a country like the USA has a hell of a lot of agency.
But the people (plural) cannot. The economy relies on it, sure, but so too does the health of the environment, the physical amount of space available, energy limitations, and the hierarchical nature of status.
What works against them is the fact that we simply cannot have 300 million wealthy folk in big houses with cars (in the US) as a physical impossibility. Add on to that the societal aspect of the fact no-one is the binman/waiter/whatever in this scenario and it becomes even more obviously nonsense, yes, but it's not the largest problem by a long shot.
Oh, and then there's the other 6.5+ billion.
If you wish to work in charitable endeavours; there is nothing wrong with that, at all. Admirable, in fact.
But it must be recognised; and I don't think a lot of article writers, or indeed people in general, realise that this is what they are doing when they obsess over 'averages'. They are tying their success to that of society as a whole, which does indeed reduce their agency; because they are powerless to affect society as a whole in more than a trivial sense unless they rise to a position of great power.
Support those around you. Be a good citizen. But focus on yourself first.