It's a reasonable question - why not use sighted evaluation as the standard:
Sighted evaluation is inherently biased by other effects - the appearance of the gear, the time of day, frame of mind, expectations, etc., which I will summarize as "mood". So think of your listening impression as the sum of the pure sound (unsighted) plus mood. While some of the effects of sighted evaluation are stable, such as appearance of the gear, the mood inputs, at least, are not stable. As a result, your impressions of the gear will not be stable. One thing will work for you over time - you will acclimate to the sound of the gear (described inaptly by subjectivists as "break in"), but in other respects, your experience will probably vacillate around the more stable unsighted impression as mood inputs change.
I believe this reversion to sound is why so many audiophiles get hung up in the upgrade frenzy. That cable that perfected their system a few months ago is no longer doing it for them. And that realization will actually have positive feedback into mood and make things worse. Off to find the perfect new tweak. Of course, you can't admit the last decision was bad, so it must now be some other part of your system...a cable, perhaps.
In sum, sighted impressions are unstable and the customer's satisfaction may revert to unsighted levels over time. For these reasons, if you are aiming for *long term* satisfaction, unsighted listening is how a manufacturer should determine preferences.
Another important consideration, in my view, is ethics. Vendors should not make claims about sound without experiments that control for effects that aren't sound. As has been said around here many times, Rolex is not telling people their watches tell better time than a Timex quartz. They might, if time weren't so easily checked.
I've seen that hypothesis voiced before, but I'm skeptical.
For one thing, I haven't seen much good empirical evidence to support it.
In every audiophile forum there are threads about what gear people have owned and how long, and there are plenty who own gear, e.g. speakers, for very long periods of time. And there are plenty of "objectivist" types who own or have owned lots of different gear. In either case, people can "like the gear" and like to experiment, and in either case there are many who can very happily settle on their choice for a long time.
For instance, me: I've had my CJ tube amps since the 90's. I've thrown other amps in occasionally but what I think I hear from the CJs seems very "stable" and reliable, which is why I've kept them so long. Further, none of my impressions of the various speakers I've owned really changed. I have a very steady, reliable perception of their sound character. But I may simply hear another speaker that has characteristics that I enjoy too, and perhaps buy them (or replace mine). I like how speakers sound different.
And the hypothesis that buying a speaker from a company that uses unsighted listening test will yeild long term satisfaction where sighted tests won't...just isn't born out by any solid evidence that I've seen. Again, go to any audiophile forum and you'll find audiophiles who have very happily stuck with speakers they auditioned and bought sighted, created by companies that don't do blind testing. You'll find life-long quad users, maggie fans, Klipsch fans, horn fans, Lowther devotees, Spendor, Harbeth...you name it, some group of people have found lasting satisfaction.
I auditioned Revel speakers among many and while they sounded very competent they didn't grab me at all the way some other speakers have.
Why would I buy speakers thinking I'll enjoy them in the long haul, if they can't even get me enthusiastic in the short haul? The speakers I bought
keep me pinned to my listening seat in ways the Revel never did (for me).
That's not to say of course that sighted influence isn't at play at all. Maybe it is. But if it is, it seems at play pretty reliably given that in the actual way I will use the speakers - sighted, in my home - my impressions remain very consistent and positive.