One of the confusions that plagues discussions of equality and inequality is a confusion between the vagaries of fate and the sins of man. There are plenty of both but they need to be sharply distinguished from one another.
The plain fact that there are large differences among individuals in incomes, occupations and whole ways of life dependent upon these things has been widely seen as "unfair," especially when the accident of birth has had much to do with these large economic and social differences.
Life is unfair. There is no point denying it. Indeed, it is hard even to imagine how life could possibly be fair, given all the innumerable factors that go into individual success or failure -- and how these factors vary greatly from one person to another, one group to another, and one nation or civilization to another.
Whatever the potentialities with which anyone enters the world, the development of those potentialities into specific skills and abilities depends on each individual's parents, schools, peers and the surrounding culture and its values. These are never the same for everyone.
Eskimos no doubt have all the intelligence required to grow pineapples but they are unlikely to have the experience to do so. Nor are Hawaiians likely to know how to hunt seals in the Arctic.
Children who grow up in homes where sports are discussed constantly, but science is not, are unlikely to have the same goals or careers as children who grow up in homes where the reverse is true.
None of this is really anyone's fault, not even that universal scapegoat, "society." These are simply the vagaries of fate.
For thousands of years, the whole Western Hemisphere had no opportunity to develop in the same way as Europe or Asia, because horses and oxen enabled Europeans and Asians to build their agriculture and their transport around these beasts of burden -- neither of which existed in the Western Hemisphere until they were brought here by European invaders.
Whole ways of life had to be different on this half of the planet from what they were on the vast Eurasian land mass. Whose fault was that?
Some ethnic groups have an average age that is a decade older than the average age of others, and whole countries like Germany and Italy have average ages that are two decades older than the average age in Afghanistan or Yemen.
Is that a level playing field? No! It is an unfair advantage to those with more experience and the increased capabilities that come with experience.