Part of the answer, I think, is in Steven Pinker’s talk, below. (It doesn’t show up in RSS readers.) It has to do with the stunning drop in violence in our human history. The ancients had violence all around them, so it entered their stories naturally. Even our great-grandparents still saw a lot more violence than we do, so they accepted it in their stories naturally. And we, as Pinker says, now have standards that have run ahead of actual behavior, so when we are being all grown-up and modern, we can’t deal with it anymore.
But the child within us ‘remembers’ the world of raw experience, before these standards. And, as Cheri has said, different people are childish to different degrees. The ‘child’ in my own personality is rather outsized, so perhaps that is why I connect to the old stories rather easily. (Emphatically not, however, to the vulgar and gratuitous violence in Hollywood).