If you have some group of naturally powerful people with long term common interests too large for unanimity and too diverse/independent for unitary leadership, voting and abiding by the will of the majority is a good equilibrium method for making repeated decisions.
All of these elements are necessary for a functional/valid democracy.
Electors must be individually powerful and valuable PRIOR TO THE VOTE or it is not in the interests of the other electors to give anything up to obtain their participation.
Electors must have long-term common interests.
COMMON interests because coordinated decision making is more costly than individual decision making, so coordination must deliver efficiencies which exceed it's frictions.
Common interests must be LONG TERM so that the minority whose interests are harmed by the present decision can reasonably expect future decisions to go their way, motivating them to stay in the game.
The electorate must be too LARGE or DIVERSE for unanimity or unified command, because debate and voting exact this toll in friction, meaning a democracy will be out-competed by any group which can accomplish the same ends with less decision-making overhead.
The prototypical democracy would be a victorious army or war-band who, having seized some new territory and distributed it among themselves, make a compact to rule together, abiding the will of the majority or the majority of some select group representing the whole.
Each elector in this case is enriched by their participation in common government. The elector-warriors in practice represent that quorum of people necessary to hold and rule the territory indefinitely.
A/t Carrol Quigley, form of government follows the practical implications of the dominant weapon system. Karl Marx claimed it was the nature/distribution of capital. Both were right. I would put communications infrastructure in this category as well.
In the Classical world, slave-based agriculture + heavy infantry formations was the dominant state format. This required a moderately sized body of trained men to fight and to supervise slaves. Consequently, you saw various forms of small-electorate republic.
In colonial America, cheap land and good tools made independent farming practical, muskets made aristocrats obsolete, and printing/literacy made theocracy impractical. The republican form of colonial and later state+federal governments followed from these conditions.
The founders and early generations of Americans had a much more realistic view of the nature of government than we do today. Free, propertied fighting men were necessary to maintain a state, therefor free, propertied fighting men were given votes.
During the Confederacy, it was hotly debated whether they should arm slaves in order to continue prosecuting the war. What was never in doubt was that arming them would imply freeing them and enfranchising them. If you have real (physical) power, you get political power.
Industrialization and mass-mobilization warfare created conditions where enfranchising the unpropertied obtained an advantage to states, and so democracy, now with a broadened electorate, remained relevant through at least the Vietnam era.
The new democracy wore the old constitution as a skin-suit debating more on demographic/class lines than regional ones. It didn't make sufficient difference to drop the trappings of the old and admit that we were in a new political order from at least the Civil War.
The common citizen was worth heeding to some degree, but not worth debating. The intervening institutions of media, bureaucracy, academia gained influence. Groups who still voted unanimously with their church, ethnicity, or union gained ground.
Somewhere in there, people came to believe a popular myth: That it was the vote that was the cause of individual power rather than it's consequence. That you could make a person powerful or important by granting them the franchise.
The US could have built a democratic state out of Afghanistan if it were not for this myth; a republic where male heads of households elected leaders by some bicameral arrangement of region and tribe would have had the legitimacy to hold power.
Instead, America mistakenly believed that our present social order and liberal democracy simply arose from giving people votes. We could wag the dog of equality and liberalism if we educated girls and enfranchised women and paupers.
So, even though the Taliban did not enjoy majority support, they had *some* legitimacy while our puppet Central Asian Starfleet had none - An Afghan could look at them and see that their constituents were "citizens" in the locally-relevant sense.
Consolidation of media, social media, and an increasing portion of the population pursuing formal education funneled communications into a smaller number of channels, making theocracy (power from the control of information) practical once again, at least temporarily.
Finally, while the hoi polloi thought the lesson of Vietnam was 'something something peace and understanding', The lesson our elites drew was that conscript armies are inconvenient; better to have a small number of professional trigger-pullers with a maximum of hardware.
The account of American history in which "The Cathedral" held power back to Plymouth Rock is flawed; most of the institutions of which the shadow (true) state is comprised don't go back all that far, or held only minimal power prior to the world wars.
Nonetheless, we do live under a shadow state today, whatever you like to call it. This has nothing to do with any conspiracy though. The electorate is no longer roughly coterminous with the powerful, and so the electorate does not wield the power.
There is much talk about how "our system" has been "corrupted" by lobbyists, corporate power, Washington insiders, etc. This is all bunk.
Our democratic system is not so much corrupt as our electorate is irrelevant.
If Wall Street, the Pentagon, the State Dept, Harvard, and the New York Times hold the real power, then those constituents are going to wield power. Whether that takes the form of bureaucratic rule-making or political donations or rigged elections is of little consequence.
The myth of enfranchisement is basically correct about broad-based democracies being awesome. But they're awesome because if you are a citizen of one, the chances are high that you have some real, personal power (otherwise, it wouldn't really be a democracy).
So, if you want to improve your life, you need to *personally* take control of your means of production, communication, and defense. Stop being an employee, stop begging for rights, stop relying on experts and media, and acquire the means to fight effectively.