Do you think driver “break in” is real?

Several components to break-in. One is strictly post-manufacture time - like Magnepan glue which holds film to frame. That's a matter of time, not use, according to the factory. The same would hold for ESL's.

Then there's mechanical change as parts wear into a tighter or looser fit. And then there's warm-up, which matters in every listening session. My Quads sound better after a day's warm-up. My Class A  SS monoblocks sound best after 10 days. My SS phono-pre is always on - wall power for standby, NiCad for listening. My cartridges always sound better after 30 minutes.

@moonwatcher You say, "That "break-in" should be required of the manufacturer BEFORE they ship them out the door."

Agreed. My higher end Grado cartridge has had no perceptible change in sound, and as I was in contact with Mr. Grado himself, I know that it came direct from the factory as a special order. Hats off to Grado.

Built a set of speakers in Juiy. They sound different now than then, subjectively Better (now at around 200 hours of use)... as experienced by a 1/2 dozen people in our Vinyl Club, family members and myself. If it is a Placebo Effect, the PE has been consistant through variously aged people, the frequency of their exposure, Digital sources, Analog sources, different placement in the Room and other variables.

A very impressive Dummy Treatment...we are all fooled and happier for it. 

I merely note that if Zu Audio can offer free break-in before they ship to you, at their price points, it seems pretty lame for more "upscale" manufacturers to not do the same.  Speakers ought to be turnkey components.  You buy them, you plug them in, and you listen. You smile if they make you happy or you send them back if they don't. 

Forcing customers to do such long break-in periods does start playing into the psychoacoustics of mental accommodation, wherein you think they sound better because you want them to, and you've become used to them, not because they do by any objective measurements. 

And I have to ask you this:  If speakers change so much after 200 hours of use, what then of the next 4000 hours? How does a mass-spring-damper system "magically" know when to stop changing, or does it?   

Certainly physical components, yes.

But electrical current certainly changes wires and whatnot over time.  It’s called “electro migration” and eventually wears out wires and connections. Takes a ver long time.

It makes perfect sense that this process works on the front end for “good”.