TES is one of the more unique games, but still it's a typical fantasy epic. It still borrows inspiration from the real world and other fantasy worlds.
Making something enteirly new is allmost impossible these day's
There have never really been a unique story EVER, everyone borrows from everyone, and that's it.
The "human races" rely on the ones in the real world, yes.
But I wouldn't go as far as this:
Nords=Norse
Imperials=Romans and Chinese
Bretons=French and...Bretons
Redguards=Songhai Empire and some Persian Empirical influences.
Khajiit= Arabian/Indian/Tibetan.
Bosmer=Celtic Druidic Culture
Dunmer=Sumerian/Babylonian
Argonians=Central African peoples. Namely a lot of cultures around the Congo. Not a very good connection other than swamp, tree-worship, slavery.
Altmer=Nazi's for the Thalmor portion, and probably the 18th century Japanese concept of Xenophobia and some Spartan breeding ideals alongside some good ole supremecy from the Europeans of the 16th-20th century.
Orcs- Mongols, Huns, and Viking berserkers.
But this here is just wrong.