Another thought related to income inequality related to this post from a couple of days ago.
Tuesday Night Buzz: Income Inequality
Another thing that changed in the early 80's was a feeling of the Great Depression survivors, that government could do/fix anything has given-way to a baby-boomer view that government was a problem, could not be trusted, and that letting people, businesses and eventually markets run free could do or fix anything. That latter view is peaking today as the baby-boom generation has reached the zenith of its power.
Unlike the Great Depression survivors, the mass of baby-boomers have no memory of what life was like before big government. They never saw the terrible working conditions, child labor, the battles for worker's unions, the elderly as a poor group, the plight of the poor, huddled-masses of the pre-war American industrial age. They grew up in good times and could make their fortune, grab their power, in a reasonably smooth running system. They only saw where government held them back. This has led to today's predominant feeling that if we let business run free the the country as a whole will be better off.
However, allowing businesses to run free has created today's corporate environment where corporations, acting as individuals, hold the real power in our government and the individual has largely been forgotten. Corporate managers are required by law to maximize profits which drives them to lobby for, or evade laws to increase profits. This search for profits also drives jobs out of the US as businesses search for lower labor costs.
So over the last thirty years profits have piled up. This has been a good thing for the corporations and their owners, basically the rich, powerful and well connected, and many would say that these profits will eventually trickle-down to the working class but the rise in inequality over these same thirty years has shown that they do not really trickle down but tend accumulate at the top.