I've wondered about this only very recntly—based, more or less; upon a principle/belief that even the worst of Apple's UI (like any element of any creator's) decisions are driven by some (misguided, as it were) motitvating intention—and, though it will take a few words, I'll offer my thoughts on the subject it for consideration: whether the Music app's landscape view might be explainable as the product of some contractual obligation agreed to by and among Apple and all those on the other side of the "table" in negotions with industry "Labels" and other content providers and/or rights-holders of the same, as apple sought rights to obtain its own rights to sell the songs, rights to such were vested in the hands of these relatively few exec.'s, and as each record label sought some way to achieve the maximum consumer exposure possible for their respective products, lest too many go unnecessarily forgotten—exiled too alphabetically remote, while listeners settled in with their audio flavor du jour instead, on repeat (with no visual or other cues to maybe listen to something else instead) and otherwise waiting until a new such favorite would present itselff; and wash, rinse repeat. This would represent the "problem" as seen by music exec.'s in my hypothesis, taken at its most extreme, but I think rooted in—and resembling closely—reality as to the habits of many, many listeners.
Accordingly, and with interests so acutely common to all such executives, yet which, individually, were fundamentally zero sum and so opposed to the others, they landed on a solution that really wasn't; a horse by committee of glue enthusiasts, if you like: they would FORCE the listener to view other products owned by each of their own constituent lahels (hence a larger number of smaller album covers appearing when placed horizontally, with an underlying assumptiion being that power of suggestion would prompt one toward one of many other options presented, while at the same time removing from view the controls and visual representation of what had been previously played. One thing that I struggle with is that the content,in either view, is already paid for and owned by the listener, but then again, I thought: most people I know aren't like me in the sense that that they don't buy many albums as such; I think this is part of the answer too.
The view in landscape mode is of album artwork, which offers both the most visually pleasing elements of a collection of audio—marketing to draw in one's attention as near as possible—and the opportunity to take that tangential interst in whatever songs one may remember then from that album, or this next one over here a few down from it. In any event, most people won't own the whole versions of these albums, but now; they are going to listen to something they know they like from it, and chances are very good, the rights to such album's music belong to a different proprietor than that which he/she had been listening to previously. And when the song(s) have finished playing and appreciation for the artist re-confirmed, Apple offers the ability to preview, and then ratably buy, additional songs or perhaps even the balance of material on these albums—music you wouldn't have thought about had Apple not "forced" you to while you, frustrated no doubt, were just reaching out to turn your iPhone back upright, because you can't see the track you're listening to or anything useful anyway, and you don't want to look at collages of other bands' pictures while you're trying' to hear your jam!
Sorry for all the brevity. It's bothered me too for some time and thought I'd write about what I had come up with for a theory. I suppose I still have not heard anything better to explain, if there even is an explanation for this floating around out there.
