So true. There are books and games and other software that I used during the mid-80s and very early 90s that I can find no record of any kind on the internet. For books, perhaps if I had the ISBN I could re-discover it. However, all I recall is the title of a book that might have been sold only in a region of the country, or a bit of software that might have sold 5,000 copies and been distributed mostly on BBSes. These items are forever lost to history thanks to obscurity combined with copyright laws.
All times lose most of their history. Thanks to copyright, DRM, and the evanescent nature of digital media, we are likely to lose nearly all of ours.