Conservative Economics and the Lower Class
Sometimes this arises from believing that they themselves are -- or may soon be -- above the cutoff such that they'll be among the people that money is being taken from in order to be redistributed down the scale. But there's also a powerful moral component. Many poorer people believe that liberal economic policies (particularly raw money redistribution, which is the first one to come to mind for such voters) are unjust, even if they benefit from them. "I've always worked hard; I don't need a handout from the government" is the mantra here.
Imagine a political party ran on a "give Stentor Danielson a million dollars" platform. I would not vote for that party, despite its clear economic benefit for me, because I think such a policy is unfair. Lower-class (white) voters often think the same thing about liberal economic policies in general.
The Frank, Klein, and Danielson hypotheses are not mutually exclusive, of course. But liberals would be better off if they admitted the possibility that conservative economics can appeal to lower class voters, and therefore were willing to make a moral rather than just self-interest appeal.