The creation and adoption of new technology has decreased the wealth of people obsoleted by new technology. Additionally, our system has grown many oligopolies including healthcare, education, utilities, etc... that increasingly leech off the system.
Poverty not only makes it harder to become wealthy but can also be debilitating. Some poverty has been alleviated by the social system but poverty's effect is lives long.
It is possible to retrain people who have been obsoleted by technology but in many cases people will end up with a lower pay than before.
I don't trust either side (this writer or Paul Graham) to come up with good solutions because both are partisan. The wealth redistributors focus on redistribution but actually cause wealth to be destroyed since they disincentize the creation of wealth for all. The other side does not spend enough energy on eliminating misery and dysfunction.