These events and ideas on record are what many religions and govenments operate by even today. I think that gives enough evidence to say that just because historians do not know of common people, they still do know something. All one knows about history is what they can interepret from any artifacts they find. If they can make some connections, then they know a little more. I look at my history book as a weird form of entertainment, because it is all guess work by people who have worked hard finding and deciphering evidence, but really have no way of knowing if what they write or judge is correct.
History has no such advantages.
They go out on a limb as a routine. It shows that history must have originally been a hobby way back when for the curious elite. Nevertheless, history is exciting, ironically, partly because of this ambiguity. I feel very lucky to have the chance to study other people. I would like to know as much as anyone about the ancient commoners, but we don't don't have the evidence.