All the conventional defences of democratic government are at odds with demonstrable centrally important facts of political life. Some of these standard defences romanticise human nature, some mathematicise it and others bowdlerise it, but they all have one thing in common: they do not portray human beings realistically, nor take honest account of our human limitations.
The result is that, from the viewpoint of governmental representativeness and accountability, election outcomes are essentially random choices among the available parties - musical chairs. Elections that "throw the bums out" typically do not produce genuine policy mandates, not even when they are landslides. They simply put a different elite coalition in charge. This leaves the current state of democratic theory in shambles. Modern democracy is based on 19th century intellectual foundations, and the empirical evidence has passed it by.