I think you're still missing the point, it's not about high frequencies we hear, it's about high frequencies that cause distortion in such a manner that it creates artifacts at frequencies we can hear...and which speakers can reproduce, and microphones can pick up.
No, I'm not missing the point. This angle has been discussed many times before.
Supersonic frequencies do mix acoustically to produce sum and difference frequencies, and the latter are indeed audible. Cymbals, for example, can have twice as much energy above 20 KHz as below it. That beautiful mash-up of frequencies bounce around the room and come back to the ear as a very complex - and definitely audible - sound. Without those
inaudible frequencies, the cymbal would sound thin and cheap.
However, it isn't necessary to
record those supersonic frequencies to get a great cymbal sound, because even though they're actively involved in the final sound, that activity takes place in the air, before getting to the microphone. By the time we encode it as digital data, the magic's already happened.
Guitar amplifiers are different from acoustical instruments such as cymbals, though, because their acoustical output is generated by components that are physically incapable of reproducing supersonic frequencies. You may very well have harmonics generated by vacuum tubes as high as 100 KHz,
but most don't make it past the output transformer and the ones that do certainly don't make it past the speakers. Nobody bothers putting Earthworks microphones on a Fender Twin, for good reason.
Your best candidate for justifying higher sample rates probably lies in virtual instruments and effects that can create frequencies beyond Nyquist: software synthesizers, distortion plugins and fast-attack dynamics processors. None of this applies to sampled instruments, nor to non-distorting processors such as reverbs and equalizers.
Even in those cases where a processor or an oscillator might generate supersonic content, a mere doubling of the sample rate isn't an effective way to deal with it. While there will be fewer frequencies to alias, there'll still be plenty of potentially harmful harmonics to make trouble. You'd really need to
at least quadruple the sample rate to be effective, but nobody's making a case for 192 KHz sample rates.
I'm not saying that there necessarily isn't
some kind of justification for 96 KHz. But over the years people have tried and tried and grasped at increasingly unlikely straws to make the case and so far nobody's come up with a rationale that's supported by science.
So Craig, who's going to be on that panel with you? Any real engineers?