Seems quite similar to selling a placebo and claiming miraculous effects. Why haven't we made it illegal?
Edit: Especially with cables/DAC/Amp. Rejecting the null hypothesis seems quite important. Headphones are pretty easy to tell apart, and it's understandable that manufacturers can only do so much since people prefer different sounds and hifi terms are quite vague.
There are a lot of reasons. One is a concept in the law at least In the U.S. called “mere puffery” which gives advertisers a lot of leeway to say exaggerated, ridiculous, or unsubstantiated things if it is not incorrectly making a false claim that their specific product is better than another specific product. This is what
@bigshot is referring to.
Another reason is that audio equipment is not a food or drug or automobile or some such thing, and the claims being made by audio companies are not putting the health, safety and welfare of the public at risk, as might be the case for false claims about drugs or food or cars or nutrition supplements, so the area of claims about audio equipment is not tightly regulated.
Another reason is that prosecutors and courts and other legal institutions have only limited resources. There is a concept that the law does not deal in trivialities. We can’t clog up the courts and waste the time and resources of legal institutions on things that are below a certain level of importance.
Another reason is that there is going to be a question as to whether the claims made are falsifiable under the law. Drug companies and other similarly critical product types have to prove safety and efficacy. But with most things what will be at issue will not be whether the claim is unsubstantiated but whether it is demonstrably false or made with a reckless disregard for the truth in such a manner as to intentionally cheat people out of their money or other material goods (i.e., fraud).
Another reason is that there is not much money or glory or political benefit in taking down audio companies who make ridiculous claims. If you are going to bring a class action who is your class? Most of the “victims” don’t even know they are victims—how are you going to get a bunch of aggrieved parties to participate?
Another is the concept in the U.S. of caveat emptor—let the buyer beware—the government can’t be the truth police for every product on the market—they have to pick and choose their battles. Consumers are responsible for some level of judgment. Again the brightest lines are really fraud or where health, safety and welfare is at risk or where one company feels it has been directly financially harmed by the false claims (or theft of intellectual property, etc.) of another company.
That’s six. I think I’ll stop there. ; )
That is not to say that if a talented lawyer took on the cause he or she could not make some headway. But they almost certainly have better ways to spend their time and effort.