Comment by WorldMaker

The article noted that at least some of the sections had been organized by publisher, so that could increase the uniformity within those sections.

Similarly, sorting and measuring all the books by height and weight may have been a part of the project of planning the shelves in the first place. It does look like an attempt at efficient packing, which I suppose you would need to keep that many books in that house and relates to the structural engineer's surprise that the the weight was well distributed as well. (Professional libraries have made mistakes in planning the weight of shelves because books are heavier than you think they are, especially when shelved. That was an interesting finding.)

All of that implied work is more shame that the likeliest outcome after the owner's passing is that the books will be separated from the shelves and the house. It almost feels like the whole thing should have been preserved as a museum. I suppose it helps that there will at least be photos and notes about it like this article.