There is a measurement. It is called "free market economics". People who have the means to purchase high end cabling are not typically stupid or ignorant, in fact just the reverse. If they like the sonic results of what they are trying in their system on an audition, and they think those results worth the money being charged, then they will commit to a purchase of that cabling. If they don't they will look elsewhere. It is that simple! If a cable manufacturer expects to survive in this highly competitive area, they had better make sure that they put out a damned excellent and competitive product at every price level that they choose to compete.If I'm going to shell out thousands, tens of thousands or hundreds of thousands of dollars on cables, I think the least they can do is show some form of test measurements. At least MIT posts technical information that's VERY useful in understanding their technology, or at least some of their technology, I sure wish they would post articulation graphs on each cable and I know they can. But they do show measurements to compare one of their cables to a generic cable. Which is a start in the right direction.
There are many retailers of cables, both brick and mortar and internet, that offer auditions. Auditioning in the context of your system and in your room is the only way that you will know what is best for you and your sonic preferences. Like it or not, there is no ideal. Audio, like any high end art is a moving target to suit variable tastes. One must try before they buy.