Age of listeners v age of speakers, is I think relevent, but I would add that a lot depends on the recording practices and electronics that existed in the period of time when the recordings were made and how they would sound on equipment contemporarily available.
I would offer the following observations to support that. We went thru a transition tube/analog with closed box dynamics or horns stuff in the 50s/60's to SS electronics w/ported dynamics, and panels, in the 70's and 80's, to digital and a reassessment of tubes/electrostats/panels and high resolution dynamic speakers in the 90's to the present.
In the early 80's I had full frequency response, phase correct, vented three way boxes, driven by SS and some fairly decent sources. The Telarc digital LP's that came out in the late 70's sounded wonderful, bass drum and all - and I think that is because they were recorded with my kind of system in mind, not Quad 57's. :-) Today, these same recordings, either the LP's or digital, but especially the CD's, sound relatively airless.
I've also found that a lot of the RCA and Merc digital 'remasters', and some of the LP's, can sound a bit thin and/or bright, which I think reflects the status of equipment in the 50's/60's.
In response to the OP's question, the 'best' speaker must judged in relationship to the 'age' of the recorded music and electronics in use when it was recorded IF you interested in the most 'musical' result and you love RCA's and Merc's you want to voice your system accordingly. There is no one size fits all. Apart from personal sonic pleasure that is.
FWIW, that is MHO anyway.
