Here’s a provocative (for me) article, “Why bother organizing your books? A messy personal library is proof of life”, by Mark Athitakis, Washington Post
This has also been true of CD and vinyl record collections, for those of us who came of age decades before the Internet and cloud storage were around. When I was writing my first three books (1997, 1998, 2002) I needed to keep old periodical hardcopies around that had been reference material, too. That’s not necessary now.
I usually order physical books that I want to read from Amazon (right now I am half-way through Connor Franta’s “A Work in Progress”, 2015, how to write a book about yourself – and he has two more to follow). It’s easier for me to find stuff and experience it rather than finding something on a Kindle or Nook.
When I move into a place, usually I can keep my most important books organized. When I moved into the Churchill Apartments in Minneapolis in 1997, I placed all the hardcopy books on gays in the military in the low case right next to my bed, because that was what I was working on. But many other older books (outside of some special ones from the family) get randomized.
Furthermore, some of the book cases are old. Stacking them in a smaller apartment now (during downsizing, which I did in 2017, out of a house) could actually create hazard of collapse. Younger people seem to be better at assembling new kits than I am.