Well, I try pretty hard to not just randomly believe anything. I look for evidence.

So, what would it look like if archeologists could infer things about the people who created various artifacts? Well, you would expect, for instance, that different archeologists would generally make the same inferences--and often enough this is true from what I've seen.

However, the narrative you tell is essentially a universal one, but we don't have universal coverage of historical artifacts--not even close. So from what you described (though possibly not from the book itself), it sounds like modern narrative mythology--with a grain of truth, like much mythology carries. Maybe all the caveats, comparative studies, and cross-referencing of different scholars (who aren't all just each others' students) is in the book. Dunno. But your description makes it sound like conclusions are being drawn that inherently go well beyond what is possible given the nature of the evidence. Thus: a myth.