One reason for income inequality is that people love the rich and hate the poor and the average. They are atleast indifferent towards the last two groups.
There is a chasm between the rich and the poor because there is a chasm between how people treat the rich and how they do the poor. People love the rich, which gives them opportunities to become richer, which makes people love them more, which avails them even more opportunities. The cycle keeps pushing them up. The same people ignore or despise average and poor people, which limits their economic growth, which causes them to become more invisible, which further diminishes their chances. This cycle keeps pushing them down. As a result, we see the rich getting richer and the poor getting poorer.
When Elon Musk said that MBA degrees are useless, people cheered for him. When I said that there is not much to be learned in business, I was considered a nuisance. When I refused to get a free MBA because I thought it was a waste of time, I was considered crazy. When Steve Jobs said "follow your passion", people turned into cheergirls. When I said that in high school, people turned into teachers.
If you really think about it, it appears as if rich people can say anything, stupid or smart; the masses would cheer for them, buy their books and products, watch their TV shows, and vote for them if they run for office. They are extravagant when it comes to benefitting the rich. The same people then bargain hard at local markets. They go to Walmart or department stores to save just a few dollars on eggs and bread.
Many who spend a lot of money on concerts to go see their favorite pop stars become financially conservative when it comes to supporting local and rising talents.
We see the same in the labor market. Recruiters try to steal workers from other companies, which allows the already employed to move up. The same recruiters do not like to see periods of unemployment on an unemployed applicant's resume. The more unemployed an applicant is and has been, the less recruiters want him.
We see the same in dating. Many women appear to like guys who are already married or in relationship more than guys who are single.
In nations and cultures where the chasm between how rich and poor people are treated is not much, there would be more economic mobility. People with disposable income would be open to paying poor and average people for goods and services. In places where people dislike the poor and practice social distancing when they see them, rising economically would be very hard. People would rather pay the rich for sub-par services than trust products and services provided by low-income people. They would feel inclined to think of them as frauds, cheats, and scammers. I mean this is the story they would tell themselves to feel good about their behavior. On the contrary, they would be blind to frauds and scams done by rich people. If you tell them, they would call you a conspiracy nut. Any evidence you provide they would likely view as fabricated.
Of course, there are many other reasons for income inequality. I am just being playful about the idolatry I see every day.