Poverty vs Inequality
From what I can tell, this is similar to the argument Harry Frankfurt makes in On Inequality. Though I do not hold the strong belief that equality has no moral concern, just that it is secondary to poverty.
If this idea holds water, I think it is a place that people with different perspectives on the benefits of free-market Capitalism can come together and agree. For this thinking, it is not required to accept that all incomes should be the same, or even draw a line for how much inequality is acceptable. Rather, this thinking requires only an initial agreement that poverty should be avoided first.