&quot;Many macroeconomic models exclude the concept of marginal utility of money.&quot;<p>I&#x27;d have to [citation needed] right back at you on that. That verges on the mathematically impossible; it&#x27;s written in the very basic most elements of economics itself. I wasn&#x27;t kidding about the math completely failing if you don&#x27;t have it; the entire concept of trade breaks down [1] without diminishing marginal utility.<p>What&#x27;s more likely happening is that you&#x27;re seeing Newtonian physics equations and complaining that the equations &quot;neglect&quot; quantum mechanics. They don&#x27;t, really, they&#x27;re in there, they just aren&#x27;t obvious, and it breaks down when pushed too hard. (So non-obvious it took centuries to discover in this case, not relevant to the econ case.) If macroeconomic models don&#x27;t appear to have a term in them directly that says &quot;here&#x27;s diminishing marginal utility&quot;, it&#x27;s only because it&#x27;s so deeply in the foundation you can&#x27;t see it through the stuff built on it.<p>[1]: You might still get trade in a world without diminishing marginal value, but one in which you still have different personal valuations. However, instead of a world in which a lot of people have a little bit of everything, which is what we observe, you would get a world in which each individual has a lot of only the thing they value the most, having traded away everything else they have to everybody else to obtain that one thing they value most. If that sounds weird, well, yes, it <i>is</i> weird, because we can&#x27;t imagine not updating our value functions based on what we currently have; it&#x27;s so fundamental we literally can&#x27;t imagine not having it. Note: This is not &quot;wealth&quot; concentration... in fact what you think of as &quot;wealth&quot; doesn&#x27;t even exist in this world and it would indeed produce a world <i>beyond</i> desparately poor as these crazy people literally focus on food to the exclusion of water, or water to the exclusion of shelter, and so on. This is a world in which one person has all the oranges, and one person has all the apples, and one person has all the blue rocks above a certain size while another person has all the blue rocks below that size. It&#x27;s not the world we live in. Diminishing marginal utility is a fundamental truth of the world, not some economic mumbo-jumbo... <i>not</i> having diminishing marginal utility would be the crazy economic mumbo-jumbo.