Unsupportable. Tolkien was only concerned with giving England a distinct history. He probably didn't care about Europe and hated everything French.
Almost everyone assumes Middle-Earth is Europe. Try holding Tolkien's famous map of Middle-Earth up to a mirror to see that it is really strikingly similar to North America, too similar to be a coincidence. In fact, he got a lot of his Hobbit surnames from actual family surnames in, iirc, Kentucky; Baggins included.
I'd say it's more of a nitpick. You're right, he was more concerned about an English mythology rather than a European one. But I'm not sure where you're going by bringing up North America...
The same goes for early europe. Plenty of people from either. There were Roman emperors who were indigenous to (Northern) Africa.
They were decedents of Roman people living there and not sub Saharan Africans.
The Roman people living there being ethically Berber, that is, African. The name Africa itself probably coming from the Afri Berber tribe. They were both Roman people and also ethnically African.
And Berber tribes despite not being from subsaharan Africa did, through thousands of years of contact, have significant ethnic and cultural admixture with various subsaharan African peoples. Not that North Africa is less African than subsaharan Africa.
https://en.wikipedia.org/wiki/Macrinus
> Macrinus was born in Caesarea (modern Cherchell, Algeria) in the Roman province of Mauretania Caesariensis to an equestrian family of Berber origins. According to David Potter, his family traced its origins to the Berber tribes of the region and his pierced ear was an indication of his Berber heritage.
Many of the top people in large empires aren't the same race or culture of the original people.
The caliphates had many groups not from the ruling elite's ethnic groups gaining high positions.
The romans had warriors and leaders of many different origins.
The mongol empire had and frequently used different ethnic groups in their armies and their leaders race-mixed with the locals.
Empires tend to be more colorful in order to control more land, its a natural effect of owning a lot of land.
https://www.heritagedaily.com/2016/05/ancient-dna-study-find...
North Africans are and always were the same people genetically. The North African emperors I am referring to specifically had Berber, not Punic or Phoenician ancestry. Which is still the dominant ancestry in North Africa today, and the Berber culture and language still lives on today.
Unfortunately it seems you are not knowledgeable of the history either of late Rome, of Carthage or of (North) Africa in general, and the authors of that website either did an incredibly poor job at it or are as well.
The modern world is just that, modern. A medieval fantasy world has to play by those rules, in its own sort of ways. They're still walking and riding on horses, and magic is exceedingly rare in Tolkien's world. People don't just travel about.