From Lansing Heritage link above:
"JBL would get its foot in the door of the broadcast and studio segment of the professional market in the 1960's as well.....
.... However, so well known was the 604 "sound", that Ed May had no trouble replicating its sonic character through subjective listening tests."
I didn't want to snip out so much, but I wanted this to appear in the correct position of this thread. What is historically explained is really important in how things took shape and that perception was more important than product, i.e. sounding like a 604 which wasn't all that great a speaker (again per the info, not my opinion) was more important than building something better (which would come later). Why? Because people don't like change. Was it the right decision? Sonically, no. Financially. YES!
This is an excellent example of compromise, and in this case well planed, well choreographed and well executed, on JBL's part.
As for some of the points about collectible, several factors play into this, not the least of which is perception. How valuable, today, do you think a tri-5 (55, 56, 57) Chevy would be had 10's of thousands not been destroyed in demolition derby's? How valuable would an Edsel be today had it not been such a flop? Uniqueness, limited numbers, breaking the mold, many factors may make a speaker highly desirable even when it's performance is not up to par with something remotely close in price. I would love to own a Dino Spyder, for many reasons. But for what they go for today there are far far superior performing vehicles and most for a lot less dough. And if more people knew they were made by Fiat, you'd have to wonder how many people would have second thoughts?
In a nutshell there is something intrinsic with collectible "gear", but that doesn't stop me from shaking my head in disbelief with many purchases, like Mach Two still in their original boxes selling for well over $500 (I believe closer to $700), plus shipping. Go figure. I think a pair of 4312, in boxes, sold for close to $1k. You know that wasn't for their performance.