I think this effect is underrated and explains a lot, for instance all the statistical correlations between good things and other good things, and, on the flip side, bad things and other bad things. For instance, why being a smoker correlates with an increased risk of having a back injury (I heard that). Or how not having a college degree increases your risk of early death from all causes. I don't know if the Matthew Effect itself has an adequate explanation, but it ties together a lot of results that otherwise seem to suggest bizarre causal relationships between unrelated things. They're all spurious correlations and the predictable consequence of the Matthew Effect.