actual new things are by definition rare. each thing can only be done once for all of humanity. after that, its an iterative process with the occasional leap forward.

if you're thinking about technical or even worse self-help books: yes - there are very few that actually bring anything worthwhile to the table. thats simply because it becomes common knowledge if its correct to a degree where it has a significant effect.

if you're however thinking of story-books than ... you're just reading similar things. there is a lot of written stories around - they admittedly usually have things like `conversation` in common, but how else would you write a book? by leaving everything blank?