I never said break in was not real. I just prefer components that are engineered to be precise and that do not drift dramatically with time. It is a simple design choice to place a capacitor in the signal path or not.
And it's a simple choice to provide the finest capacitor available in the best equipment and that means IF you have a cap, it's a VERY high quality cap, it will take a VERY long time to break in.
It is a simple design choice to either place a capacitor in a passive crossover (where it adds distortion) or use a line level x-over filter.
I use an active crossover with my speakers but they were designed that way from the start. To say it's a simple design misses some very important points. To execute an active crossover properly you need a separate amp for each frequency. I agree that's the best, but to call it simple is inaccurate. Such a design generally requires a lot more parts, amps, cables and space. Not every designer (or every customer) is willing to do this.
That leaves us with caps inside the crossover, a design that represents most of the speakers out there, yours and mine perhaps the exception. Regardless if the caps are inside (my) active crossover or in a passive design, they play an enormous role in performance and ALL great quality caps take forever to reach 100% performance.
There is no design exception to this unless you have system with no caps.
My point was to simply challenge the idea that burn-in that sounds greatly different is a good thing . It often implies overly simplistic designs that are commensurate with a goal of "purest signal path". Unfortunately, the engineering reality is quite the opposite - through added design complexity one can dramatically increase precision and robustness of product performance from changes in temperature, ground loops, cables, interconnects, power, noise, component aging etc.
I think every designer in the business would agree with that and most would say they worked to achieve that goal and provided same for their customer, within the limits of budget given for the project.