The Simple Story of Evolution

'Genesis was written so that simple people could understand it'. For people who hold this view what they usually mean is, 'God really used evolution, but evolution is too hard to communicate to people who lived long ago, so Moses wrote about how God created in 6 days.' However, today evolution is communicated to children through critically acclaimed children's books. This begs the question: if God really did create over millions of years couldn't Moses have written it that way?