Johnk, "Cone materials, surrounds,spiders, cone shapes, crossover parts, cabinet designs, binding posts sets, internal dampening all have improved for transducers."
I agree with you, mostly...
Although, I will say that some of the things we're told strike me as people congratulating themselves for what amounts to the normal incremental improvement one sees in most fields that survive over a period of time. We're living in a time of evolution, not revolution. I believe that is a reflection of the fact that precious little in the way of resources are now dedicated to the craft.
A couple of years ago, I attended the annual Tube Tasting that Jonathan Weiss puts on at Oswald's Mill. Although some of the discussion was above me, and some has been forgotten, a most informative presentation was given on the team of folks who designed the 12" RCA full-range driver way back when (late 1940s?). It was a real breakthrough, and pointed the industry to where we have come since. I don't want to get into too much of the minutiae, but suffice it to say that regarding the level of talent, resources, money, time, and passion that RCA threw at the development, I believe NOTHING like that will likely occur again for a very, very long time.