It's not survival that matters in evolution, it's reproductive success. The comment is sort of a joke calling attention to that; it's a joke because mere predisposition to such belief is not necessarily as strong an effect in our selection anymore -- people often have more kids when they're lower on the economic bracket, instead.

Though...being lower on that scale does seem to correllate with a sense of anxiety and nervousness about the world and how possibly-hostile it is...