You seem to be comparing opposite extremes: physical books stored carelessly (in a well-heated and ventilated house, mold shouldn't be a problem) with digital b

You seem to be comparing opposite extremes: physical books stored carelessly (in a well-heated and ventilated house, mold shouldn't be a problem) with digital books stored very carefully (you were careful about DRM-free formats, etc.; and if you have stuff from the 80s, you doubtlessly have made backups and transferred it from device to device several times. I have some digital stuff of mine from the 80s and 90s, but I've also lost a lot, in spite of being conscious of the importance of backups). On average I think what the post says stands. Assuming some minimal, but not very careful upkeep, physical books easily last for 100 years, digital material for much less. By the way, an anecdote: some time ago, I found a bookshelf in an old house of a branch of my family, which contained books dating more than 100 years back (some were from the 19th century). The house had been abandoned for many years, so the books had been exposed to the elements. Most of the books were softcover, and they crumbled on touch, some of them almost literally crumbled to dust. But the few hardcover ones endured, with moisture stains on the cover but I still have them and they are perfectly readable. Before that, I usually preferred to buy softcover books because they are lighter, more comfortable to read, cheaper and take less space. Since that day, if I really like a book (or think I'm going to like it, due to author, etc.) I always try to get it in hardcover.