"Oligarchy" is a form of power structure in which power rests with a small number of people. These people may be distinguished by nobility, wealth, family ties, education or corporate, religious, political, or military control. Such states are often controlled by families who typically pass their influence from one generation to the next, but inheritance is not a necessary condition for the application of this term.
"The iron law of oligarchy" is a political theory, first developed by the German sociologist Robert Michels in his 1911 book, Political Parties. It asserts that rule by an elite, or oligarchy, is inevitable as an "iron law" within any democratic organization as part of the "tactical and technical necessities" of organization.
Michels's theory states that all complex organizations, regardless of how democratic they are when started, eventually develop into oligarchies. Michels observed that since no sufficiently large and complex organization can function purely as a direct democracy, power within an organization will always get delegated to individuals within that group, elected or otherwise.
(The above excerpts are from Wikipedia)
Democracies will remain oligarchies till they are controlled by humans. I believe - unbiased Artificial Intelligence, to some extent, has the potential to solve this problem of democracy. We need to identify and elect that particular human who has vision and courage to apply Artificial Intelligence to the Democracy.