There’s still a strong cultural bias though that is likely location dependent. I have lived in very wealthy towns for which there was not a single Ferrari or Bentley around (or any other luxury car for that matter). That ownership of an expensive car requires some degree of wealth is absolutely clear, but the inverse doesn’t follow —- average cars don’t indicate average income. It could be that the study finds that certain ethical biases are related to people who buy expensive cars, which is not the same as saying that certain ethical biases are related to wealthy people. Millionaires who drive Toyotas could simply exhibit different ethical standards than millionaires who drive Ferraris.