> From inside one of those new cultures (who are cool and unique in their own ways, sure) it can be easy to miss the significance.
A lot of assumptions.. I live in Europe and belong to supposedly one of the fairly ancient cultures according to this definition. It doesn’t seem any less silly to me because of that.
Unless Japan is supposedly exceptionally special somehow in that regard? I don’t think it is, most unique things about its culture have their roots in the 19th or 20th century (just like European countries or the US).
> Japanese settled Japan by skimming Wikipedia but that I'm not sure
The Ainu might have. The settlers/invaders from China or Korea whose culture later developed into what we know as Japan only began arriving in the archipelago around 300 BC (so less ancient than the Greeks or Romans). Also much closer to the establishment of US than to first nation people migrating into the Americas.
No. Greeks, Romans, Vikings, Slavs, Turks, Arabs, Mongols etc, different peoples have their respective roots for sure, but those roots are elsewhere. Once you move across the ocean and mingle with a bunch of others coming from radically different backgrounds and histories, different mutually unintelligible languages and incompatible religions it's a completely different story than if you live at the same locality, speak the same language and carry broadly similar values and beliefs as N generations and thousands of years back. Except for first nations, people of US and Canada are still very much guests on their soil if you compare those timescales. But from a viewpoint of one of those new cultures (who are cool and unique in their own ways, sure) I can see why it might be easy to not see that.