Income equality is steadily on the rise, unfortunately. The thing about this question, though, is that it completely ignores the fact that the gap in America is different than the gap in Brazillian. Brazillians at the bottom have almost nothing, whereas Americans on the bottom have access to quite a bit.
People's income is not going up but the cost of living is increasing. Upper class people don't pay as many taxes proportionally as do the middle class. Jobs are much harder to come by than they were and they don't pay as well. The rich keep getting wealthier, thanks to their investments and government welfare for large corporations. Income inequality is on the rise.
It is a known fact that income inequality is real in the United States. There have been several news articles on this topic and several studies that have been completed. The fact of income inequality is real, it is not a debate or matter of opinion. You can say poor people are to blame for their situation but these facts say they aren't.
The middle class is disappearing. The two fastest growing sectors of the economy are value shoppers, like the Walmart crowd, and the luxury crowd that can afford to spend a lot. What used to be middle class shopping is disappearing fast, because incomes are more and more inequal with every passing day.