There are many reasons why this argument does not hold water. In every economic system inequality feels terrible. People don't really have an absolute scale of inequality where they get upset if it crosses a certain threshold. It's all a matter of how much do they believe they can achieve the top spot.
A starving artist doesn't get super upset at wealth and the lavish parties of a successful artist because he truly believes that one day he'll get there. Tomorrow Jay-Z could become world's first trillionaire but a struggling hip-hop star would still not support high taxation on his assets.
The resentment starts when he believes that achieving that high status is not possible (which is not true for America) OR when he loses the existing status (i.e status loss).
The status loss theory explains things like Communist revolutions, rise of Christianity in the decline of Roman Empire far more than income inequality.
In fact in the United States, people at the low end of income almost never support the income inequality theory, it's almost always done by high social status non-religious left-liberals. For the people at the low end of income curve (but not like starving actors/artist/authors) believe that in the US, people have a shot at becoming rich, but because of loss of economic opportunity due to globalization, immigration etc has resulted in creation of this situation.