American Indians and Aboriginal Australians have been living like that well into historical times, and people were around to document their lives and societies - there's no real reason to suppose that humans at the most primitive state of society were living any differently. In a way, it's the one style of social organization that has truly stood the test of time; everything else has been a glorified self-imposed experiment. We're all guinea pigs living in self-enforced captivity.
> American Indians and Aboriginal Australians have been living like that well into historical times...
They're not time travelers from the past. They're our contemporaries, who are every bit as 'modern' as us. They just made a different set of choices along their historical arc.
> ...there's no real reason to suppose that humans at the most primitive state of society were living any differently.
At the same time there's also no real reason to suppose that primitive humans were living any similarly.
We just don't know. Any attempt to frame this differently is just ideology.
> If these people never went through the social evolutions the rest of the world underwent, they are indeed travelers from the past.
Logical error. That they didn't go through the same social evolutions that we went through doesn't mean they didn't go through any social evolutions at all.
(And indeed they must have; even keeping their societies static takes conscious effort, in the same vein that conservative reactionaries today aren't at all the same people, ethically and sociologically, as the simpler ancestors they try to emulate.)
