All revolutions happen because of mass unemployment of the middle class. Not the aristocracy, working class, or decrepit poor. The middle class is the group of people of artisanal or union class. They are secured in either a specialized role or high paying job for a somewhat general labor role. If they lose their job en masse, finding a job becomes very hard. So now not only do they have time to kill, but they have influence in swaths. Aristocrats likely end up backing groups that begin to rise up. Which helps fan the flames of discontent.
We've seen it happen France in the 1700s, Germany in the 1800s and 1900s, Russia pre WWI, China in WW2, and Spain during WW2.
Imo, the US is far from this happening. The only people who often complain about radical income disparity live in one of the major cities. Granted it has merit, but there is a sizable amount of people that live outside of those HCOL areas. City people forget that there is a very wealthy, affluent, and secure America outside of cities.