I personally don't think an 8-page checklist (6 pages for normals) to fly a Piper Cherokee or Cessna 172 is the safest approach or most sensible operational tool. Many pilots seem to agree and make up their own checklists that they actually use with only the "killer items" and I think that probably increases safety; certainly it increases safety over the 8 page checklist that stays in the map pocket for the whole flight. Why doesn't the factory do that? Well, if they remove something from a checklist and a pilot comes to grief, they're thinking of how it will look in a courtroom. "No charge to add something to the list..."
You'd probably enjoy reading Checklist Manifesto by Dr Atul Gawande: http://amzn.to/1ZlTjoJ I read it years ago, but I seem to recall he did cover some of the processes and social aspects of checklist usage.