There are many different "rich economies" (as measured by National Income) with different levels of inequality. Consider, for example, the United States, Japan,

There are many different "rich economies" (as measured by National Income) with different levels of inequality. Consider, for example, the United States, Japan, Germany, and Sweden (in descending order of inequality). I think you're arguing something of a strawman - that there should be no inequality. Most people other than hardcore Marxists aren't arguing that - they are arguing over what levels of inequality are justifiable.