An important part of the article is a debunking of the different myths explaining how this happened:
MYTH #1: INEQUALITY IS MAINLY A PROBLEM OF POVERTY.
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The real divergence in fortunes is between the great majority of Americans and a very small, extremely wealthy minority
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MYTH #2: INEQUALITY IS MAINLY A PROBLEM OF EDUCATION.
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Being highly educated won't make you into a winner in today's U.S. economy. At best, it makes you somewhat less of a loser.
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MYTH #3: INEQUALITY DOESN'T REALLY MATTER.
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America actually has less social mobility than other advanced countries: These days, Horatio Alger has moved to Canada or Finland. It's easier for a poor child to make it into the upper-middle class in just about every other advanced country -- including famously class-conscious Britain -- than it is in the United States.
A lot of this has been accomplished through Republican tax policy and the associated misinformation.
the administration has engaged in a systematic campaign of disinformation about whose taxes have been cut. Indeed, one of Bush's first actions after taking office was to tell the Treasury Department to stop producing estimates of how tax cuts are distributed by income class -- that is, information on who gained how much. Instead, official reports on taxes under Bush are textbook examples of how to mislead with statistics, presenting a welter of confusing numbers that convey the false impression that the tax cuts favor middle-class families, not the wealthy.
In reality, only a few middle-class families received a significant tax cut under Bush. But every wealthy American -- especially those who live off of stock earnings or their inheritance -- got a big tax cut. To picture who gained the most, imagine the son of a very wealthy man, who expects to inherit $50 million in stock and live off the dividends. Before the Bush tax cuts, our lucky heir-to-be would have paid about $27 million in estate taxes and contributed 39.6 percent of his dividend income in taxes. Once Bush's cuts go into effect, he could inherit the whole estate tax-free and pay a tax rate of only fifteen percent on his stock earnings. Truly, this is a very good time to be one of the have mores.