What transducers and under what controls and test parameters?What kind of "burn in" are you referencing? Transducer burn-in is very real, and I have measured it on several occasions.
(Pro tip: re-do your room EQ every couple months or so after getting new speakers till the drivers stabilize. Also re-do the eq when the weather significantly changes as temperature and humidity will significantly affect how your speakers perform in your room.
Not necessary if your listening room has very good temperature and humidity control.)
Burn in of cables on the other hand is nonsense for standard conductors like copper, silver, and aluminium unless we are talking about corrosion, in which case conductivity gets worse and not better.
There might be some very exotic conductor used in scientific applications that changes it's conductivity under sustained load, but I doubt someone would use such a conductor in an audio cable, at least I have never heard of it.
There are some amps or DACs that need to warm-up to a certain temperature before operating at optimal performance, but that is different from burn-in, and should only take a few minutes at most.
As for tubes, they do burn-in, but that just means the tube needs to be replaced. Tubes are designed to work best when new and typically only degrade with use, similarly to light bulbs.
Temperature and humidity "significantly" affect how speakers perform? How much change in temp and humidity? I would posit that it would need to be dramatic as compared to a normal living room conditions to have a significant effect. Have you measured this and under what controls and paramaters?
Transducers built with quality components, and quality crossovers or self amplification should under no circumstances take "months" to stabilize. Don't think that's arguable on a scientific forum.
I agree with the rest. If you're proposing that room eq measurements prove speaker burn in and significant response to atmospheric conditions, I'd say there are other reasons for inconsistent results. Makes me wonder if Amir is tightly controlling these factors in his garage using his Klippel... don't remember mention of it. If its 30 degrees that might be something, but even then I'm skeptical of significant change.
Change my mind...