The sources of inspiration. Some of the people behind the lore really know their stuff. Some knowledge of Eastern cultures and religions will help you spot them.
I'd also argue that in the case of the dunmer culture, the sources of inspiration are so varied that it creates a sort of inspirational ambiguity. I'm going to pick a terrible example here, but the orcs from Warcraft 3 are carbon copy of African tribesmen, and that's about it, that's all the cultural equivalents they have to real world models.
But the dunmer have both a tribal society, a certain jewish xenophobia, south italian numismatics, bedouin lifestyle, an honor code, sharp class distinctions, strict religious orthodoxy, monastic institutions and pilgrimages, saint worship, etc.
While the nords are clearly inspired by scandinavian culture, the dunmer sources for inspiration are so varied that it leads to a sort of blurring of the line between the real world (inspiration) and the fiction (outcome), because there is no single equivalent in the real world for the dunmer culture.
I have not previously given much thought to the similarities between Dunmer culture and those on Earth, but your description and my memories now make me think very strongly of
Saudi Arabia.
Tribalism: the country was formed as an alliance of tribes led by the Sauds and still is basically this to a large extent.
Xenophobia: Foreign workers stay in compounds, Western influences resisted and they gave us Osama bin Laden. One might even compare those compounds (and USA military bases) with Imperial forts and towns like Pelagiad and so on.
South Italian numismatics: Coins? Sorry, but I do not follow.
Bedouins: A few nomads still wander the central desert I believe.
Honor code: probably.
Sharp class distinctions: You could be a prince pf Saud with a significant portion of the national wealth entailed to you or some commoner of another tribe living in a hovel in which you cram your wife/ves and children.
Strict religious orthodoxy: perhaps more than anywhere else (perhaps North Korea moreso, but that seems different).
Monastic institutions and pilgrimages: Hello, Mecca. How does the Hajj itinerary compare to that tour of pilgrimages one must take to join the Tribunal Temple?
Saint worship: Broader Western Asia, maybe, but I believe Islam has saints, Caliphs, prophets etc. with disagreement about some between sects. Also the migration story, the wars and so on of the Chimer/Dunmer/Velothi seem to resemble the Arab conquests and the spread of Islam, the fights againsy the Persians etc..
Also, IIRC, pre-Muslim Arabs and/or Berbers had ancestor worship and the Tribunal Temple seems a bit like a Caliphate.
So, perhaps the Dunmer ARE a carbon copy of an Earth culture, but one we are less likely to notice as it is less copied or less visible in general?
