The basic principle of democracy is to prevent the accumulation of power in the hands of a few. A society in which 90 % of all wealth is owned by 1% of the population is not democratic. Some have more than they need, many have too little. The USA is a feudal society; a few have a lot, and many have too little. (Republicans call protest against gross inequality , class envy). Elections obscure that we live in a feudal society. No wonder populists rage against the elite of both parties.
In a meritocracy differences in merit lead to differences in income. That is good. However, the USA is not a meritocracy. Few get rich by working; most wealth is inherited, not earned. The USA is a plutocracy where wealth buys power and power buys wealth. Icicles are a fitting metaphor. The bigger the icicle, the more dripping water it collects. Ultimately, the icicle collapses under its own weight.
Invention deserves to be rewarded. Most inventors make some money on their invention but only the owner of the duplication process will get rich. Ford and Apple are good examples. It is very lucrative to own a duplication process that costs next to nothing. Examples are Google, Facebook, Amazon.
When people pay for your work you must be contributing something to society. That is good. Consequently, when you make a lot of money, you must be very good. That is seldom the case, Wealth is often an indication of power, deception, luck or inheritance. No virtue involved.
Some inequality is good. Better performance based and work, ingenuity and initiative deserves better reward. But differences in performance do not warrant to 'earn' in a day what others earn in two years. A difference of factor 10 or 20 between a living income and a top income seems enough income disparity. Income above twenty times a living wage should be taxed 100%. Personal capital above twenty times the average can be taxed 100% .