Voters have a rational disincentive to hold their legislators and politicians accountable; politicians react to voter ignorance by being captured by special interests when "the public good" is broadly and not narrowly defined; bureaucracies become self-serving; all of which promotes government failure. However all that being said, democratic countries tend to produce better outcomes for their constituents that autocratic regimes.
According to Public Choice Theory:
Most people have a rational disincentive to be informed on the subjects.
One of the chief underpinnings of public choice theory is the lack of incentives for voters to monitor government effectively. Anthony Downs, in one of the earliest public choice books, An Economic Theory of Democracy, pointed out that the voter is largely ignorant of political issues and that this ignorance is rational. Even though the result of an election may be very important, an individual's vote rarely decides an election. Thus, the direct impact of casting a well-informed vote is almost nil; the voter has virtually no chance to determine the outcome of the election. So spending time following the issues is not personally worthwhile for the voter. Evidence for this claim is found in the fact that public opinion polls consistently find that less than half of all voting-age Americans can name their own congressional representative.
Public Choice theory further postulates on the nature of politicians, even if the public good could be defined in a pluralistic society (same source):
Public choice economists also examine the actions of legislators. Although legislators are expected to pursue the "public interest," they make decisions on how to use other people's resources, not their own. Furthermore, these resources must be provided by taxpayers and by those hurt by regulations whether they want to provide them or not. Politicians may intend to spend taxpayer money wisely. Efficient decisions, however, will neither save their own money nor give them any proportion of the wealth they save for citizens. There is no direct reward for fighting powerful interest groups in order to confer benefits on a public that is not even aware of the benefits or of who conferred them. Thus, the incentives for good management in the public interest are weak. In contrast, interest groups are organized by people with very strong gains to be made from governmental action. They provide politicians with campaign funds and campaign workers. In return they receive at least the "ear" of the politician and often gain support for their goals.
In other words, because legislators have the power to tax and to extract resources in other coercive ways, and because voters monitor their behavior poorly, legislators behave in ways that are costly to citizens.
These two conditions, tied to bureaucratic self-dealings and interest (in the Weber definition of the life-cycle of bureaucracies) leads directly to government failures:
But public choice economists point out that there also is such a thing as "government failure." That is, there are reasons why government intervention does not achieve the desired effect. ...Congress has frequently passed laws that are supposed to protect people against environmental pollution. But Robert Crandall has shown that congressional representatives from northern industrial states used the 1977 Clean Air Act amendments to reduce competition by curbing economic growth in the Sunbelt. The amendments required tighter emissions standards in undeveloped areas than in the more developed and more polluted areas, which tend to be in the East and Midwest.
However, all that being said, democracies do tend to produce better security, both financial and physical outcomes, for their constituents, and are more vibrant technologically and intellectually, than autocratic regimes, a theme that William McNeill demonstrably proves in the Pursuit of Power