It has to do with governance, laws, and policies. The US is supportive of the wealthy remaining wealthy even though most don't actually contribute the value they acquire. Most of the population work very hard for very little wealth over their lifetime, yet they create and contribute more positive growth to the world than the rich do. Trickle down economics is false and the old tale of the rich creating jobs is also just that, an old tale. The rich getting richer is a symptom of a dysfunctional system.