Most audiophiles seem to be men in their 50s+, which makes their claims of exceptional hearing extremely dubious. Degradation of hearing with age is a virtual certainty.
If audiophiles tended to be teenagers I'd be more inclined to believe them. But old guys? Old guys with a long habit of listening to loud music? Their ears are not golden.
All of that was gone when we arrived in our twenties. I couldn't hear the TV anymore (younger people: That applied to analog CRT TVs back in the neolithic). I was tested in the military when I was 22. They didn't even bother testing anyone up to more than maybe 14kHz - intense volume would anyway be needed to hear that.
I can't imagine even very careful people will be able to hear a particularly wide audio range when they're 50+, not even people who walk around with ear plugs all the time for protection (some audio engineers do).
When it comes to hardware: if you have a great and clean signal chain, good ears, decent monitors +/ good room, good headphones, you can record and hear the difference of good gear (diminishing returns though, you are paying for throughput (channels), latency, or even just build-quality/brand (Apple esque) etc at some point).
Of course marketing adds hyperbole and takes certain aspects into woo territory. At the software level: sampling rate can (depending on programming of individual plugins) make a difference in your mixing session (you get nasty artifacts, like EQ cramping, in plugins that don't have internal over-sampling).
This is all the professional gear with a track record rather than the "prosumer" gear (maybe that's the definition of audiophile you were connotating).