As to the History of Writing, we can only go by examples that have been found, on Clay Tablets, as nothing inferior would have survived.
It could well be that systems of " writing" in some form, perhaps keeping a tally of goods and stocks of stuff say, may have existed long before writing on Clay Tablets, it just never survived, if carved on wood or whatever.
Pure Hunter Gatherers of course were as TD hints above, unlikely to need or to use writing. But later Hunter Gatherers who were moving toward being agrarian may possibly have done so. If the need was there. And that is the point, most advances and changes by humans were driven by need.
There is no doubt at all that humans have been around, a lot longer then the Bible allows for.
If we say that as recently as 150,000 years ago mankind was fully sentient, fully conscious of " Self", which is what makes us Human in part, what was the Bible God doing for 144,000 (LOL) of those years until he made Adam ?