Working within those forms is part of managing reader expectations, which is a key component of making a story appeal to a given reader, but the expectations we have around form and length of stories are not derived from some optimization method synchronized with humanity’s ability to interact with literature.
Front Matter, Back Matter, Does it Matter?
You probably don't think about it - I hadn't given it more than cursory consideration - but there is a lot that goes into a book beyond the simple writing of the story. Front and back covers have to be designed. ISBNs have to be purchased. Copyrights have to be obtained. Fonts have to be chosen, and sizes: page sizes, font sizes, margin sizes. Pages have to be numbered, prefaces and acknowledgements have to be written...I could go on.
IGC Publishing 