In some sense, all governments are democracies. The only difference is who gets a vote – and that decision is based on who can inflict violence on others.
In low complexity societies, it’s not particularly hard to create an elite that monopolizes violence in society.
As societies become more complex, it becomes harder and harder for that elite to maintain their advantage in violence without surrendering power to the people who make that violence possible. If all you need to oppress the peasantry is a sword, a horse and some armor, you don’t really need the peasantry to support you. But if those peasants need to build you internal combustion engines and semiconductors, you can’t accomplish that by beating them over the head and looting their barn.
Indeed, you’ll notice modern complex societies with authoritarian governments are actually egalitarian compared to historical societies. Being a peasant in China isn’t all that great. But if you’re a scientist, an engineer or a doctor, it’s not a bad life. Sure, you may not be able to start your own Alex Jones-style youtube channel without running afoul of the monopoly-of-force folks, but neither are random soldiers showing up to loot your barn.
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