It is my contention that the broad libertarian consensus has largely concluded that Democracy is incompatible over time with the fruits of capitalism, which have brought unimaginable prosperity to the masses of the world.
Why is this?
"A democracy cannot exist as a permanent form of governement. It can only exist until the voters discover that they can vote themselves largesse from the public treasury with the result that a democracy always collapses over loose fiscal policy, always followed by dictatorship. The average age of the world's greatest civilizations has been 200 years." -- Alexis de Tocqueville
"Democracy is nothing more than mob rule, where 51% of the people may take away the rights of the other 49%." -- Thomas Jefferson (disputed) -- good statement regardless authenticity.
When it is cheaper to buy political favors than to compete in the marketplace, the rational actor will do so -- general Public Choice theory
An uninformed populace will often vote against measures that benefit the majority. (Largely due to economic ignorance) -- Bryan Caplan
"To a first approximation, democracy in Britain is fake. The real power lies with the civil service" -- AMcGinn
"the postwar Western system has assigned almost all actual decision-making power to its civil servants and judges, who are "apolitical" and "nonpartisan," ie, nondemocratic." -- Menicus Moldbug
Essentially, the claim is that Democracy in any real sense is necessarily bad for any goals of actually improving happiness over time.
There is a dispute over whether some other system (formalism, charter cities, free state project, seasteading, monarchy, disentangled republic) is likely to be any better. However, at least as far as I've been able to tell...the idea that with public choice theory + the civil service + stupid voters, there's not a shot in hell for democracy to move in libertarian directions. The only thing that can happen is for the government to continue to expand.
There are naysayers. As far as I can tell, Will Wilkinson and some others (perhaps Brink Lindsey) either disagree with the analysis or recognizes some advantages among the creeping filth of political control.