Yes, I think that there will be income equality in a capitalist society, because it is more equal to have people given what they earn rather than be given the same no matter what. With the income being based on work in capitalism, we are all equal in that we are given what we deserve.
Capitalist society, by its nature, is inherently contradictory to the concept of income equality. There will always be a division between the classes, and without an salary cap on the upper classes and strict government regulation of the markets, the necessary evil of capitalism requires there to be class gaps.
Under a capitalist society, which is inherently structured to value money over human individuals, profit motive over ethical values, and corporations over the voices of citizens, there is no hope for income equality to ever be achieved. We must work to think of alternative solutions, especialy now that the gap between rich and poor is so vast.
Capitalism does not support income equality. If you look at the income inequality in the United States you can see what capitalist society supports. The only way to reach any sort of income equality is to add socialist ideals with the capitalist ideals. Capitalism will always leave people poor and socialism will always leave people on equal ground, even though that isn't always warranted. It's best to mix the two.
There will never be income equality because some people will gain more than others, and that is an unchangeable truth. In TRUE laissez-faire capitalism, the people who work the hardest get the most money. In pseudo-capitalism, which is many modern nations including America, big businesses and politicians will have the most money, with a few exceptions. In systems with even less economic freedom, there will be a distinct upper class, usually the most politically powerful people, and a lower class, usually everyone else. In any system, some people will have more political power than others and will use that to gain more money. The only system that does not do this is laissez-faire because the government is not allowed to interfere.