Anything more resolving than 65 year-old speakers?

Room size and acoustics has as much to do with it as the speakers themselves.

Back in the early 70s after attending the Woodstock Festival I was impressed with Altec. Not the ginormous ones at the festival but Altec produced a bunch of residential grade outstanding versions. Models such as 14, 15, 17, 18 and 19 seemed to fit in many home listening areas. I settled on a pair if 19s and still have them now. I like them for the horn drivers, 802-8G with the tangerine phase plug that tends to soften the horn for near field listening. The 15" 416 woofer provides plenty of the base. I do find in different rooms the best position is about 15 feet from the speakers. On the plus side with vintage gear from Altec is the fact that Great Plains Audio can still repair almost all the Altec drivers back to original new form. A disadvantage is that size of the box is often a concern and at 30 inches wide the 19s can be a bit large for many living rooms and listening areas. I am a little surprised that Altec is not mentioned above in the top 12 while the Klipschorns are. I had them and sold the pair after comparing them to my 19s.

The Quad Electrostats were one of my references back when I jumped in the deep end of hifi yet again back around 2008. I ended up with newer Ohm Walsh speakers that I still have and seemed to hit the mark overall.

More recently , I also added KEF Ls 50 metas and those take detail to the nth degree I’d say as a result of technological innovation baked into those and other newer KEFs. White papers on how they do it are readily available.

I currently use Quad 2912s, Janzens and Martin Logans. They are all better real world speakers than Quad 57s — better bass, better extended treble and better dynamic range — but with the right kind of music, I agree with the OP that the 57s’ midrange is still in a class by itself. 

Great as the AR3 was at the time, at the same time AR featured in its Grand Central demo room and alongside one of the subway tunnels leading from the station to the bus station, a system featuring the AR1W woofer, the Janzen 130 midrange electrostatic (130 dispersion), and the Ionic "charged air" horn tweeter.  These, with the AR's on end, woofer next to the floor, created pillars that essentially were transparent from 30hz up into the 20-30,000hz range.  If I recall correctly, they were driven by HK Citation components.   They created an absolutely three dimensional soundstage with the best sonic holography I have ever heard.

A note on Klipschorns, Altecs, etc. and other horn speakers.  At the time the Klipschorns came out, James B Lansing (JBL) had a front loaded horn speaker that was even a bit bigger that sounded even better, although it's bass didn't go quite as low.  It featured a tapered, curved 3' wide by 4' high horn driven by two15" woofers, and for the midrange-treble the first appearance of the famed JBL "Potato Masher" horn.  My dad had one in the living room driven by a Newcomb 25w power amp (with preamp umbelical). We never had the Klipsch home, but I did get to hear it in the same corner spot in the store as the JBL, and to my then 12yr old ears the Klipsch sounded peakier and not as refined.  A year later I "officially" became an audiophile as I built my own system....so unless you started your audiophile journey before 1953, I lay claim to the "oldest" audiophile here in the forum. 😏