>> I find your characterizations of why horns aren't more popular in America based more on a bunch of tropes than real information. <<
Hmm. And I find your defense of horns propagandic. Yes, I've listened to 604s in proper closures. And most of the other classic domestic and cinema horns. As well as modern horns ala Avantegarde Acoustics. Yes, in the grand scheme of things they can "sound good." Would I take any of them over Zu today? No, they aren't as integrating and most use crossovers. That's a first-order loudspeaker sin for me.
The magazines didn't explicitly kill the horn in America. But they trumpeted an alternative. With stereo requiring two speakers, the acoustic suspension speaker killed the horn by vastly expanding the constituency for domestic hifi in the late '50s through the late '70s by making audio space requirements practical and mitigating the spousal objective factors. And then horn loading and other ported techniques emulated the suspension design's form factor. But most of those compact "horns" weren't very convincing. At any time in the US, the percentage of consumers who are oriented to and receptive of high end audio is miniscule, and the SET subset of that is a more diminutive still. Horn loudspeakers will never be a significant trend in hifi here because the enabling factors (small, musical amps, spousal acceptance, willing space allocation to hifi, etc.), have scant presence, and the inhibiting factors (finicky placement, solid state / substantial power market, spousal objection, trend to large houses reversing) are pervasive.
A speaker from Zu's upper line has more coherence, most of the efficiency and dynamic life, better dynamic unity and is much more accommodating wrt placement and more flexible wrt compatible amplification. Notwithstanding the crossovers dependency in most horns, horn speaker systems can sound admirable. It just doesn't work out that way in the domestic interiors most people have to work with.
Are Voxativ's Arpeggio Due and Avantgarde Acoustic's Duo XD the same because they both use horn principles? Not exactly. The one that can achieve coherence in nearly any room is the Voxativ, but it's not the one that shouts horn.
Phil