You perhaps overestimate the utility of writing outside urban civilization - and underestimate the immense difficulty of its invention. Not only is symbolic tho

You perhaps overestimate the utility of writing outside urban civilization - and underestimate the immense difficulty of its invention. Not only is symbolic thought required, but so too a cultural substrate which can find use for, agree upon, and preserve written works. One man may invent the wheel; only a people can invent writing.