Johnk did not say that only his opinion/experience counts. He simply said that experience trumps speculation. Unless one has actually heard the type of systems he is talking about, it is mere speculation that modern designs are inherently superior. I have heard these systems. A number of people of people posting here apparently have heard these systems and have commented on some issues that they have with the sound of these vintage systems. I agree with them that deep bass response is limited. But, there are many aspects to the sound of these systems that I have never heard matched by modern designs--the sense of speed, the incredible dynamics and scale (the feeling that a lot of air is being moved to produce a BIG sound). To me, these systems are particularly matchless when they are playing softly.
I have heard a fair share of modern designs and I do like many of them. None of these systems that I like share a particular technological approach so I would never insist that they have to be time/phase aligned (some are, like the full range electrostatics that I like) or that they must be active speakers. I would not rule anything out based on technology employed, materials used in construction or measurements--I would insist on listening and deciding based on auditioning the speakers. That is why I essentially agree with Johnk --experience (i.e., hearing the speakers) trumps all the conjecture about this or that technology.