Rich as fiction?: historians and history-writing?

I was stung by something I read recently on the dust-jacket of a work of popular history. The reviewer declared as a form of high praise that the book was 'as richly detailed as a work of fiction'. This took me very much by surprise. What does it tell us about how history-writing is perceived? First, that it is not richly detailed compared to fiction, and second, that it is less interesting or less readable than fiction. For a work of history to be interesting, stimulating and readable is unusual; it brings it closer to the field of entertainment, and thus fiction.