My guess is it's mostly because the physical book's cover's always visible in your environment, even when you're not reading, so you see the title and author's name a lot more. Some e-readers put the cover on when in sleep mode, but that's small, black-n-white, only on one side (no spine) so it's easily covered up, et c.

Books also often put some or all of that info at the top of every page or every other page, while many reader apps hide it most of the time, I suppose to save space for body text.