@mrmb — Thank you for your thoughtful engagement with my posts, and for your reflections!
Your description of moving along a continuum — from eyes-closed focused listening to barely registering that music is playing — touches on something historically underappreciated. The intense, reverential, silent attention we now treat as the "correct" way to receive music is actually a fairly recent invention. If I recall correctly, Mozart expected that people would talk during performances, and took delight when audiences applauded a particularly nice effect mid-movement. Historian James H. Johnson, in Listening in Paris, argues that Parisian audiences only fell genuinely silent around 1830 — and that this shift was itself a historical event, not a natural condition.
From the book: "This book grew from a simple question. Why did French audiences become silent? Eighteenth-century travelers’ accounts of the Paris Opéra and memoirs of concertgoers describe a busy, preoccupied public, at times loud and at others merely sociable, but seldom deeply attentive. Why, over the hundred years between 1750 and 1850, did audiences stop talking and start listening? The answer is anything but simple. This transformation in behavior was a sign of fundamental change in listening, one whose elements included everything from the physical features of the hall to the musical qualities of the works."
In short, what drove it was partly the music of Beethoven, which demanded more concentrated listening, and partly a middle-class social project: restraint of emotion in the concert hall became a way to distinguish respectable audiences from the working class, and the old spontaneous bodily response to music was recast as "primitive." In other words, the reverential silence we've inherited is as much a class artifact as an acoustic one. This is replayed in the fetish we see in the hobby for pretty, shiny, expensive gear. Axpona as a commercial-religious ceremony.
Brian Eno made exactly this challenge to one type of listening explicit in 1978 with Ambient 1: Music for Airports, where he argued that music could be designed to be, in his phrase, "as ignorable as it is interesting" — something that rewards attention when given it, but doesn't demand it. This was a direct provocation to the idea that unfocused listening is inferior listening. What you're describing across your Echos, your surround rooms, and your SoundLab rig is essentially a lived version of Eno's argument: different modes of attention are not a hierarchy with eyes-closed critical listening at the top — they are different relationships with music, each valid on its own terms.
The risk in audiophile culture — and I say this as someone who has spent considerable effort optimizing a dedicated room — is that we can turn the focused mode into a moral standard and subtly denigrate everything else. Your son's Klipsch system is not a lesser experience; it is a different one, and possibly freer.
Two other things in your post worth noting. Your observation that A/B differences "evaporate" once the comparison is done and you settle into listening is one of the more honest things to read on this forum. It maps directly onto what controlled listening research consistently shows — that the salience of differences under comparison conditions is not a reliable guide to their significance under normal listening conditions. It's a nice reminder that people with limited budgets can become audiophiles, too.
And your closing question about whether the upgrade chase is hardwired into human nature is not rhetorical: there is genuine behavioral economics literature suggesting that anticipation and acquisition reliably produce more dopamine than possession. The hunt, as you say, may be the point.