Sure they are, but that was not the argument I was half-jokingly making. What I was saying was that you can't hide meaningful amount of difference in tax rates

Sure they are, but that was not the argument I was half-jokingly making. What I was saying was that you can't hide meaningful amount of difference in tax rates between then and now in business lunches (which to the best of my knowledge are still around). On a more serious note though I would consider the law of diminishing marginal utility and its impact on economic activity.