The existence of compound interest and exponential growth mean wealth inequality will become more and more extreme over time as generational wealth accumulates.

History teaches us that extreme inequality and class resentment leads to societal collapse. First there is civil unrest, then revolution. We have seen the beginning of some serious civil unrest this year.

From a purely self-interested point of view, if you value living in a peaceful and stable society, you ought to be concerned about wealth inequality. Generational wealth is one of the major factors here.