Wealth divides in and of themselves don't cause civil unrest. Wealth being highly concentrated in 1-2% of a society is the historical standard, not a modern aberration. A large middle class is the aberration. Great wealth gaps will be tolerated as long as the people feel they have mobility and a chance of improving their lot. Else, order has to be kept purely by force or other forms of coercion. In other words, the Have Nots will accept their lot in life as long as they reasonably believe they have a shot at becoming a Have.
That's being compounded by the differences of the Information Age vs the Industrial or Agricultural Age, not least of which is instantaneous mass communication available to all and the ability of charismatic individuals to spread dissent and rally followers in a much larger way then ever before. People are thirsty for meaning and purpose. Many people don't have that in their lives. Combine with a general feeling society isn't working for them, or is actively working against them, and it's easier for those charismatic individuals to create followers and convince them to protest or riot or even kill. It's even better if you can convince them it's all someone else's fault and that someone else is easy to dehumanize.