Low efficiency, direct radiating speakers with voice coil-fitted drivers - as they're mostly represented today - have improved in a range of areas over the last ~50 years. ESL's fundamentally haven't.
The pro segment of speakers have seen their improvements as well, not least for their intended applications and to accommodate in some cases a smaller size factor in the LF-region via different designs and much more powerful drivers, but as has been pointed to already a selection of vintage pro drivers have a dedicated following due to their sonic characteristics. Their lighter overall moving mass (incl. voice coils) - some of them with field coils and others with Alnico magnets - and lower power handling can lead to a "snappier" presentation as well as a fuller, more organic tone, not least as a distinctive feature at lower SPL's where they seem to come better to life. To me at least, while finding there's definite merit to their popularity, there's also sometimes a particularity to their sound that's not necessarily about "neutrality." Seeing also the prices of such units being often preposterously sized it becomes a niche market to a select, sometimes wealthy following of audiophiles that pursue of specific sonic imprinting.
In any case I'd take most any of a range of older (or newer), larger pro horn speakers - typically aimed at cinema usage - over modern (or older) day low eff. hifi dittos with their vastly more realistically scaled, effortless and uninhibited presentation. Most domestically aimed horns/horn hybrid speakers fall short here as well being they're size constrained; while it may make them a better fit with the spouse and caters to interior decoration demands, a compressed size factor with this segment of speakers really robs them of their fuller potential. It's not about domestic or pro application here, but simply what serves the design and the physics involved - in a home environment as well.
And that, physics, is what the pro segment of horn-based speakers got right from the beginning, many decades ago, so even while they were less extended in the frequency extremes they got the important basics right in a way that newer, smaller domestic designs in the same segment can only dream of achieving. And that's not about age, but rather - to reiterate the above - what complies with physics the best way possible.