Hi @ryder
I’m skeptical. No, not a "cable skeptic", as I have spent significantly more money on cables than any true skeptics ever would, and believe that they can indeed make noticeable differences. But I am also a strong believer in diminishing returns, and am skeptical that a very expensive XLR could be significantly better than an expensive one, assuming that the materials and build quality of both were what one should expect for the price levels that you mentioned.
I suppose that if one cable employed silver, or silver and copper, while the other was pure copper, there could possibly be some difference in SQ, but that would be more a function of basic design, and not necessarily cost.
Like you, I don’t A/B in the classic sense, mainly because it would be extremely difficult and expensive to do so. But like most audiophiles, I have listened to a variety of cables for extended periods of time on my own system, and with music that I am very familiar with. I don’t consider confirmation or expectation bias to be significant factosr, as there have been instances in which I really would have liked to have preferred a recent acquisition, but found the opposite.
Over the past ~20 years I have used Audience cables more than any other, and, after a couple of fairly recent "grass is greener" forays into other brands, have returned to the fold. I use Au24SX speaker cables, and Au24SE XLRs, both of which were purchased used. The SX was the previous top Audience model, and the SE were one step below. So, would a pair of Au24SX XLRs make a difference? Or a pair of their current top model, the Front Row?
I don’t know the answer to those questions, but I am skeptical that any differences would be significant. I say that partly because when it comes to cables, I believe that even well-established companies with products made with good materials and based on good design principles typically feel compelled to create model hierarchies, with the top-end, of course, being targeted to those who can afford to spend serious money in a quest to squeeze every last ounce of performance out of their systems. So I assume that the differences between the top models, and those a step below, are very likely to be small, if they even exist!
My two cents.