Flat to 20kHz is infinitely preferable to having a good sized spike in the FR at the edge of hearing. Instant listening fatigue!
There are things that make a difference, and things that don't. Just about every player, DAC and amp that is performing to spec is capable of spectacular sound. The wild card is the speakers/headphones. Money put there is wisely spent.
The best way to improve an existing system is through proper application of EQ and DSPs. That will make a HUGE difference in even humble sound systems.
If by 'here' you mean the gear forums in general, maybe you're right.
If you mean this sub forum, ask yourself this question: Who's more likely to have nagging thoughts about cable upgrades, new gear that is praised in subjective reviews (after much hype measurements often show not so amazing performance), new FOTMs, new tube rolling or op-amp swapping ideas etc.? I personally can be happy with what others here would consider low-fi, as long as I have my music library (!) and DSPs such as EQ, crossfeed etc.
Back to topic, when I see a review that includes a section where the reviewer says he can hear differences, for example, between different USB cables using the common vague subjective terms, I know I cannot trust that person. The guy/gal may be completely sincere, but to come back to my previous example, it's like a patient that is being treated with inert pills telling you that those pills cure diseases.
It seems even praising a hi-fi enthusiast here - as in Judge Judy--"no good deed goes unpunished" As I have said before I am not 100% convinced about "the sound of cables" but we are all different why try to mold people into one set ideal. What one person hears another cant --that's a physically proven fact . my wife's hearing is acute a lot better than mine. Why try to apply physiological limits to human beings just because they don't fit in with science. Is there a great fear that if science is proved wrong [and it has many times] that the "sky will fall down" that's bordering on a type of fascism. If somebody has a different view to me then that's life. I could put a viewpoint but never in a "I know better manner". Kids at school get picked on and called names if they are fat--WHY because they don't "conform" to societies "ideal"--society is wrong in that respect as that can harm a child for life and give them " complexes" something that nobody can do to me as I don't accept societies "ideals" and would fight to the death for that cause.
The reason I was drawn to this sub-forum over all the others here is because it touted the application of science to this hobby. I still don't comprehend those that seem "scared" of science, to the point of reflexively refuting scientific results whenever it conflicts with their "beliefs." Science has endured for a reason. All our modern comforts (like our sound systems) are direct evidence of its efficacy. What's the point of just saying it's wrong when it doesn't jibe with your world view? Which of the two is more likely skewed?
I'm not punishing anyone. Saying that happy people are rare here is not exactly a "good deed".
And when it's physically proven that there is no difference but some people still hear differences it has nothing to do with how good their hearing is.
It was proven in multiple studies that the placebo effect is real. "The placebo effect points to the importance of perception and the brain's role in physical health." If the placebo effect can improve your subjective condition, it can easily change what you hear.
Some studies suggest that there's still a chance of the placebo effect occurring even if the patients were told about it beforehand. In other words even if people are told that two cables perform identically (and physically really do perform identically), some might still hear differences.
You really, really should read a book about science, maybe start with the Wikipedia article. What societal ideals have to do with any of this, I have no freaking clue.
Anyway, when you see new members asking for advice because they're not happy with their new headphones and you see some people suggesting to get/upgrade to a dedicated amp, external DAC (because internal often doesn't fit the audiophile "ideal") and sometimes even cables, instead of just suggesting to return the headphones or try to spend a bit more time with it, you know what the "ideal" headphone audiophile is expected to own.
So no, you would not.
so quality is based on sales success?
i'm returning all my gear and buying some Beats in that case!