Why high-end cable manufacturers don't post measurements?

Why the interest in measurements?
OP please tell us all how YOU measure SQ.

All these wanna be engineers of truth, justice and the American way. Their purpose is to save you from yourself and reveal the audio deep state that's conspiring to steal your money. 

Enough of the crackpots already.

All the best,
Nonoise

It is only partially true. Most of the manufacturers I have seen do post measurements. Of the length. Some, rare ones I think, do even post gauge. That would be about it, but is hard to catch them saying "never post measurements".

Because there aren't any measurable differences between any reasonably designed cables.

Check out http://www.ielogical.com/Audio/CableSnakeOil.php for how cables interact with components. Be sure to read the Garen Galeis papers. Also https://www.stereophile.com/content/what-difference-wire-makes from 1995.

Nor any sonic differences that can be readily identified blind.

It depends on the system. Some systems will confound the most skilled listeners. Some systems are relatively immune to cable effects. Other combinations are like flipping a switch.

Thank you ieales.  Great info.