America had income equality at its beginning. The Pilgrims made a pact to share everything as they de-boarded the Mayflower on November 11, 1620, to found the Plymouth colony (or as they called it, "the first colony in the Northern parts of Virginia"). Long before Karl Marx came along, the Pilgrims invented communism.
And they almost starved.
Those who could work felt exploited as they received no more than those who could not work, or whose work was not as productive. Call it greed all you like, but without the incentive to work harder, these young men had no incentive to do more than the least to get by. Not being able to reap the fruits of one's labor is slavery, and that is what Pilgrim communism was.
Without the able-bodied planting the crops, there was no harvest. Without a harvest, the people had nothing to eat. Governor William Bradford wrote of men and women going to work for the Indians just to eat. Rare is the history text that includes mention of white people volunteering to become indentured to Indians. But they had to eat. Bradford wrote of a man collecting shellfish who "was so weak, he stuck fast in the mud and was found dead in the place."
Bradford called this period "the starving time." Of the 102 passengers, only 52 survived the first year. Those who survived decided to ditch Kumbaya communism in favor of capitalism. Not only did they survive, but they thrived. The bounty they produced they shared with the poor and invalid.
That has been the history of America ever since. Not the only history. To be certain, slavery existed in all 13 colonies. But slavery was as dead-end an economic system as communism was. People need an incentive to innovate and create. And employers and society benefit when people do that.