Income <> Wealth.
I do not dispute that the income gap between the rich and poor has increased. However, the wealth gap has not.
Have a look at Table 3 in this article. It shows the percentage of wealth owned by the top 1% in America, from 1922 to 2004. Notice that it has been significantly higher in the past. And significantly lower. In fact, it fluctuates quite a bit between about 25% and about 40%, with a couple of outlier years.
Here’s another analysis, which only goes to 2000, but which uses estate tax data and comes up with the same basic numbers: Top Wealth Shares - Evidence from Tax Returns.
So the question is, how come income share is increasing at the top, but total wealth is not? One reason is because the tax system is progressive, so the after-tax income is not increasing as fast. Also, a study which I also linked to in the other thread has shown that people with high incomes are predominantly clustered in areas where the cost of living has increased much faster than in areas with predominantly poor people. So the real adjusted income gap is only about 1/10 that of the raw income gap. Add into that estate taxes and other factors, and you have a situation where wealth is relatively stable even though income at the upper end has been increasing.