It's not as improbable as you think. The concept of bartering still exists within Star Trek it's just that you do not need to barter to make a living.Skeleon said:
Anyway, let's just say that the abolishment of money is part of many utopias, because people believe envy and socio-economic differences just go poof once it's gone.
But even if you got rid of all the money, those differences would still exist; they'd just be enforced through different means such as owning production facilities, having access to special food, clothing, cars and so on.
Human beings tend to compete with each other all the time, if not with money then with something different.
An utopia where most of these differences are gone is pretty beautiful (think Star Trek) but also pretty much impossible unless humanity itself changes (which is very improbable).
In our earliest years as an intelligent and social species money didn't exist. We worked to survive. Today money acts like some sort of middle man between work and survival. A world without money isn't too difficult to imagine, although I do think that humanity currently cannot exist in a world without some sort of currency. Once the basic necessities of life become trivial in terms of cost and effort, money will have much less importance and thus our evolution above using any form of currency would begin.
