In the case of vintage speakers, the picture is especially cloudy because so few people have actually heard the great sounding speakers from the 1930s and 1940s. Especially in carefully set up systems. Too many are making judgments based on what they think old speakers should sound like or what they recall from hearing Altecs or Klipschorns years ago, rather than actual experience.
For myself I came to the vintage world and to horns in particular quite reluctantly. For whatever reason I am very sensitive to the "honk" or "shriek" produced by many horns. For decades each time I heard a horn speaker, I had the same negative reactions and wondered how anyone could tolerate such a colored sound. Then I had a chance to hear some speakers using Western Electric horns and drivers and discovered how good they could sound. As noted by several posters in this thread, a really good vintage speaker has a special musicality that modern speakers just don't provide, at least in my opinion. And certain horns do NOT have the honk or shriek that drives me the wall. One of those horns is the Western Electric 32A which can blend seamlessly with a large paper cone woofer, and fortunately the Altec version of the 32A is still readily available. My own speakers use the Altec 32A with compression drivers and woofers that qualify as vintage but not from as far back as the 1930s. I won't say my speakers can compete with the Shearer speakers described by the OP but they do things for me that are musically satisfying in ways that modern speakers do not. And that includes modern horn speakers such as the Classic Audio Loudspeakers (heard half a dozen times but only at shows) and Avant Gardes. Other folks might not react the same, but that just goes back to the diversity in this hobby. To each his own.