I think Clarke was imagining a world so abundant that poverty would be a thing of the past. I don't think he was indifferent to the poor, but rather imagined a world where needs are automatically granted. The trouble is, it's a fantasy world. Economics is as basic to humans as thermodynamics is to the physical world.

Economics entails facts which are uncomfortable to some people. No matter how advanced a society gets, scarcity — if only scarcity of time — is a factor which has to influence our actions. Star Trek has a world without money, because you can get anything you want from a replicator. But imagine what a world where people can replicate anything they want, without limit, would be like. Where would they put all the stuff? Replicate a planet for storage?