I don't have a historical answer for you, but this question might be better for /r/AskAnthropologists (or /r/AskAnthropology, idk which sub is the better one). This is going away from historical studies and into cultural ones.

Maybe some historian will come in here and make me look like an idiot for suggesting that, but I feel this is more anthropology's domain.

edit: askanthropology is the better one; the other has 0 posts lol

Generally speaking, states in the past were "the goverment of the powerful, for the powerful, by the powerful", thus all the goverment systems and politics prior to the Industrial Revolution and the Enlightenment were solely concerned about that and that includes the "exceptions" in the list as well. Nobody cared about what the "people" thought or wanted, and for the large part the powerful tried their best to snatch the most from the poor and undefended while avoiding uncontrollable revolts in the process. The powerful were influential individuals in a society like the religious strata, or folks who would force things in their favor like warriors, but it also ocasionally involved other folks (like some merchants).

A monarchy is a natural model for this kind of state building. Everyone desires that their descendants inherints what you were able to build in live, that's why we have extremely similar inheritance laws in every single nation in the world. The powerful back then wasn't different and built their political system so it would be of a dynastic nature. The leader part, the "king" comes from the need to get coherence that unify's all the powerful's locals with similar interests and he, like the rest of the system, was often dynastic as well, for the very same reasons.

Sometimes the powerful managed to organize themselves under an oligarchy, that means, the goverment of the few. That is what all the exceptions were, and that is what monarchies truly became in practical effects through most the world during the early modern period as well (16th century and onward). What limited this organization in the past was that oligarchies struggled to make a coherent millitary force to support themselves in power, since rarely there was enough universal agreement to decide who and when had to put his neck on risk in the battlefield, meanwhile kings can to some extent pressure or force lesser nobles to actually lead and fight when required, and they were also pressured by those same nobles to do the same when required.

In any case, warfare in the past was largely fought by elite warriors which came from that very same class strata (the powerful), with assistance from "commoners" (more like middle class warriors, like mercenaries), though this is a rough generalization and millitary organization varied greatly. The Chinese managed to break this cycle and created a bureacratic oligarchy state by equiping commoners with Crossbows about two millenias ago, so all the powerful required to gauge war was money to equip and quickly train those folks rather risking themselves at the frontline. The same began to happen in the Middle East, Europe and elsewhere with the introduction of Gunpowder Weapons about six to five centuries ago.

This moved the power from the ruler, whose main task was to movilize an army of elite warriors from his same social stratta, to the oligarchy. Oligarchs rather movilizing an army themselves began to pay, train and equip commoners to wage the wars for themselves, though the natures of warfare still required things such like cavalry or officials which were poorly suit for commoners to handle, so both systems cohexisted for a while.

This reality would only change as the Press and the Enlightenment set new ideas of politics and society in an emerging new middle and middle-high class, alongside the nature of the Industrial Revolution which made material goods (including weapons) and intellectual goods (like public schools) far more affordable at a big scale. This allowed things such like Nationalism and Mass Conscription to exist, which at the same time allowed the concept of "the goverment of the people, for the people, by the people" to become a practical reality (though you would also argue that this concept and the old oligarchies - now called corruption - cohexists in tandems even today).

Your premise is simply not true. Let's arbitrarily say that human history began 200,000 years ago (from when the earliest widely accepted fossils of our species have been found). For the first 190,000 years—95% of human history—we can safely assume that practically all humans lived in small, egalitarian groups that had no government or fixed leadership of any kind.

Between 10,000 and 5,000 years ago, this egalitarianism gave way to early forms of stratified political organisation in most (but not all!) of the world. It's not easy to say what forms this might have taken, but as a very broad generalisation these were societies that were probably organised on the basis of kinship groups, where decisions were made through negotiation within and between these groups, strongly mediated by convention and shared cultural norms. It would have been very difficult for a single individual to autocratically "rule" more than their extended family.

Between 5,000 and 2,500 years ago the first autocratic forms of government appear, but they do so in a very small number of places, and compete with other forms of governance such as temple-states, oligarchic republics, and chiefdoms. Only in the last 2,500 years or so—less than 2% of human history—has autocracy tended to dominate; first with the "age of empires" in Europe and Asia, then the imperial or monarchical governments that tended to follow in its wake.

I also can't stress enough that at each one of these (very generalised) stages involves a lot of geographical telescoping. To say that most of the world was governed by autocracies over even the last 1,000 years is extremely Eurocentric. It may be true of a fair proportion of the "Old World", but it was not the case at all in Inner Eurasia, Subsaharan Africa, Australia, the Pacific or most of the Americas.