In traditional media, the audience doesn't know how long is remaining in the story. So, false endings and other devices work well.
You never know when a play is going to suddenly end.
A story being told can end suddenly or go on for hours or more.
A song or a band playing can go however long.
A ritual can last indefinitely (or can be extended / ended suddenly)
Stories appearing in magazines, or short-story collections have an unknown end.
Serialized magazine stories can have an indeterminate ending.
In modern media, you always know how much is left.
DVDs display time remaining (minus credits)
In books you can feel how many pages there are left (although indexes, other junk at the end can make it tricky)
CDs sort of give you a hint based on the track number, but people can put in hidden tracks & things.
It'd restore the mystery, and make plot devices work a lot better.
It would also reinforce the (in my opinion) correct way to read a book - to really consider whether or not this book is worth reading at all, and if not, stop reading, without feeling a need to finish it.
Kindles should give the option to not show page numbers. DVD players should let you disable the movie time display.
It's not really possible to do it with books, though.