I would agree that representative democracy has some really huge problems.
At the fundamental theoretical level of what democracy actually is, it’s basically communism. Now, that sounds like something a communist would say, but in a way, they have a point. The underlying assumption of democracy is that the people collectively own everything and so it is the will of the people, through popular vote, that determines how all resources are allocated and what rights the citizens have or don’t. Democracy is a form a communism where the people haven’t yet realized that they own the means of production. Of course, if the voters actually started exercising this control that they theoretically have, the democracy (along with the nations) would collapse.
From a more practical perspective, the execution of representative democracy is bad too. Despite the theoretical benefit of democracy, which is that the citizens can protect their interests with their votes, the reality is different. In reality, voters are too ignorant and apathetic to represent their own interests, and so the politicians who they elect turn out to be the best liars and manipulators rather than people who will serve the interests of their voters. Of course, the best manipulators are the people who have the backing of the media, the banks, and other multi-million dollar institutions, many of which aren’t even based within the country.
The claim that representative democracy outcompeted monarchy or nobility is in many ways true. RD can be competitive because it serves the interest of the vastly powerful monied interests, who are the true rulers in a representative democracy, and once those people rose to power in the West, then the systems (like representative democracy) which give them the most control receive the benefit of their power and can outcompete alternatives.
Really, all nations have oligarchies. Even absolute monarchies, since the king must trust in numerous important people to carry out his will as well as advise and inform him. All systems have a minority of people who have the majority of the power. The downfall of modern Western nations is that our oligarchs have no loyalty to the nations that they rule, they in fact see themselves as apart from these nations and at odds with the people, and so their rulership basically revolves around plundering their host nations for wealth and power. This differs from how a king or nobleman might view his dominion, as the source of not only his power but his prestige and the source of the same for his descendants and name: his legacy. So essentially being a part of the nation even if socially distinct from peasants.
In modern Western world, our rulers (the corporatists and their underlings the politicians and bureaucrats) have betrayed their nations in the most dishonorable way imaginable. A treasonous and vile subversion of the goals of democracy using the mechanism of democracy. What am I referring to? Well, in a democratic republic, what can the elites do when the voting citizens don’t support their agenda? Well, just get new citizens who will support their agenda. This trend in democracy we see now in just about every liberal democracy in the West is the most evil perversion of leadership possible and it likely wouldn’t be possible were it not for our democratic governments and the monied interests that dominate them.