Do speaker cables need a burn in period?

Claims that remain controversial among the relevant experts (e.g. I’ve seen many EEs say why the technical claims made by audiophiles or expensive cable companies are nonsense), and where the explanations are dubious, and the evidence almost purely anecdotal.

>>>Two things, professor, claiming that many EEs say technical claims made by audiophiles or cable companies are dubious is not only second hand evidence but it’s also, you guessed it! an Appeal to Authority. What about the many EEs who say the claims are not (rpt not) dubious? You’re just going to ignore those, right? Furthermore, anecdotal evidence is still evidence. It is in fact empirical evidence. Hel-loo! Sorry, professor, care to try again?

Imagine you went to your doctor with a sore throat. The doctor says "Well, obviously you have cancer of the throat!"

You ask "why?"

The doctor says: "Because throat cancer can cause sore throats."

And you say" But...can’t many other things cause sore throats, like maybe I have a cold or a flu? Shouldn’t you show me how you have ruled out those other causes"

Doctor: How DARE you be so dogmatic as to question my diagnosis!

prof, have you lost it? 

Do any of the nasayers believe in equipment break in? Tube break in? Speaker break in? 

Cables - no break in
Tubes - once warm, no burn/break in; they just degrade over time from day one and sound best when new. "Burn in" for a day or so is best used to determine that the tube is stable and not about to fail.
Speakers - yes; they are motors and some of the materials that flex need to break covalent bonds to perform optimally
Cartridges - same as for speakers
Turntables - yes, motor/platter bearings need to wear the metal surfaces over time to reduce micro-machined irregularities
Electronics (DACs, preamps, amps, CD players) - no, (except for the CD motors, sled and rotational) but the electronics do need warm up to function optimally.
People ear/brain system - yes, the biggest single audio component that is the most variable of the recorded/playback/listening experience. More "brain burn in" is always a good thing. No wonder many sip the etoh or smoke/vape the herb while listening.

Steve. There are wires in all the devices you stated. You might want to consider that  part of the break  you are hearing is in the wires!