Kids these days!
By which I mean anyone younger than 65, apparently.
From 1454 to about 1984 or so, a span of approximately 530 years, the unit of book layout was a two-page spread in which, other than in special circumstances, facing pages balanced. That is to say, they had matching top and bottom margins. When type was made of metal, this convention was reinforced by the nature of the medium.
In the mid 1980s, computer-drive typesetting had evolved to the point that some systems were capable of pagination, rather than just spitting out long galley proofs that a human paste-up artist cut up into pages. (I did that for a few years.) However, the pagination algorithm wasn’t quite smart enough to produce balanced spreads on the first try. There was tweaking involved.
Seemingly, the generation of graphic artists who grew up with that technology never learned that balanced spreads were something desirable. And publishers’ production editors stopped expecting them. I’m fuzzy on which came first, but we’ve now reached a state of affairs in which the most popular layout program, Adobe InDesign, does not have a function for automating the ability to balance spreads. There’s no good reason it doesn’t; the function would be much easier to implement in the software than some of the other sophisticated features must have been. But hardly anyone now working in the field knows or cares enough, apparently, to demand that capability.
As a result, publishers, even major publishers that are household names, are churning out books in which there has clearly been no attempt to balance spreads or maintain a neat appearance at the bottoms of pages. I mean, sure, I do it, and so do at least some of my peers. But we’re a dying breed.
Kids these days!