Annotated Unequal Scenes - USA (unequalscenes.com)

"Some inequality of income and wealth is inevitable, if not necessary. If an economy is to function well, people need incentives to work hard and innovate.The pertinent question is not whether income and wealth inequality is good or bad. It is at what point do these inequalities become so great as to pose a serious threat to our economy, our ideal of equal opportunity and our democracy."
—Robert Reich

An important observation. What might create such a tipping point? Is there a way to look back at these things historically to determine the most common factors that would create such tipping points?