The far-left (Marxist and left-anarchist) critique of mass democracy is that it is merely a mask for rule by a plutocratic capitalist class. The libertarian critique is that democracy is two wolves and a sheep voting on what to have for dinner. The far-right view is that democracy merely replaces the rule of the corrupt few with the rule of the incompetent many, a system of mob rule by an oligopoly of special interests and demagogues. All of these critiques are correct.
A system of localized democracy among a relatively homogeneous population with low exit costs may be viable. I have long thought the best system of government (if there can be such a thing) would probably be one where the highest body of government was chosen through a sortition system (the way jurors are chosen now, more or less) combined with demarchy (many decision-making groups are given narrowly focused and temporary functions).
We’re used to thinking hugely well of democracy. But interestingly, one of the wisest people who ever lived, Socrates, had deep suspicions of it.