An oligarchy at best, autocratic at worst, totalitarian regime
With the exception of the old Free Rasalhague Republic and some other minor states, this is true of all major states in the BT universe. They are all ultimately ruled by singular despots who have very few checks on their power. The difference between the Houses and the Clans is that the Houses inherit their despots while the Clans choose their despots through meritocracy (albeit a meritocracy of insane trials by combat) and very limited democracy (voting by trueborn or bloodnamed warriors only).
In fact, one could argue that the government of the Rasalhague Dominion, with powers shared between the Khan and the Prince and both checked by a legislature representing spheroids, freeborn, and trueborn alike, is arguably more like a modern, real-world, western liberal democracy than any other major BT state. (That doesn’t mean it is, just that it’s closer to.) Even when governing as a coherent whole, the most democratic Spheroid body, the FWL parliament, ultimately defers to the Captain-General through a long-standing emergency order.
that controls its population literally from birth (iron wombs, genetic selection) to how their remains are to be handled after death.
This is mainly the trueborns, which represent less than 1% of total Clan population. The vast majority of the freeborn population has normal reproductive freedoms.
Yeah, the eugenics program is weird and alien and it’s the center and ultimate work of Clan civilization, but it’s practices remain the exception, not the norm.
They brainwash their population and strictly control them. They separate them in castes without any way for a "lower" caste to gain access to a higher one. Just imagine what the life of a freeborn waste management caste member should be. Worst than any serf in any feudal system anywhere.
Yes, a more systemic difference between the Clans and Houses is the tightly held command economies of the Clans' where vocations and tasks are assigned, not chosen, by the workforce. There are shades of this in the Cappie and Snake societies, but the Clans take it to an extreme. In the end, it doesn’t really matter as all general BT populations are sheeple. Otherwise, it would be impossible to take and hold worlds of millions and billions with a regiment or cluster of mechs.
What I don't get is how they are still alive. Even with the hit of the succession wars, the production capabilities and human resources of the IS should considerably dwarf those of the clans. After the initial shock, a protracted war should not have gone the way of the clans. I understand that the narrative required it, but it is so counterintuitive that it jarred my sensibilities.
In WWII a BIG factor of the allied win was the fact that they outproduced the germans. By a LOT. In our case, if the IS took total war seriously not only the Smoke Jaguars would have been eliminated. But they didn't and now we have an encroaching ilClan waiting to pound on Terra itself.
The Clans are modeled, more or less, on the Migration Period peoples (Visigoths, Ostrogoths, Lombards, Vandals, Huns, etc.) and later “barbarians” (Vikings, Mongols, etc.). If you just looked at overall numbers, production, organization, or even technology, those peoples should not have been capable of doing things like sacking Rome, threatening Byzantium, bringing down any number of empires and kingdoms, or creating some of the world’s largest empires. But unlike their “civilized” counterparts, those entire societies were geared for war, and they had practiced endemic warfare for centuries. They were still the underdogs, but when it came to warfare, they also had certain advantages that the “civilized” world lacked. Like their “barbarian” forbears, what the Clans lack in sheer numbers or economic production, they potentially make up for with singularity of purpose, practice, efficiency, determination, and ferocity.
Moreover, even the best-run “civilized” empire will fall on hard times. And that’s when the “barbarians” most often sweep in and take over. And that’s arguably what’s happened to four of the major Spheroid powers (Elsies, Republic, Leaguers, and FedRats). The historical precedent you want to look towards is the fall of the Roman Empire, not WWII.
Lastly, it’s important to mention FASanomics. Factory production, military size, etc. is driven by plot, not investment and demographics, in BT. For all we know, the Clans actually do outproduce the Inner Sphere militarily despite their smaller population and presumably smaller economic base. Given the number of mechs they destroy in Trials of Position, Trials of Bloodright, and Grand Melees alone, they might have to!
Don’t get wrong, there’s a lot to dislike about the Clans. But like everything in BT, it’s not all that cut-and-dried or black-and-white.