I often have older customers tell me they don't want to spend a lot on gear because their high frequency hearing is diminished and they wouldn't be able to appreciate the quality it offered. WRONG! To illustrate the point let me recount an experience I had early on in my audio career.
At 18, and just out of high school, I went to work at the local high-end shop (we didn't use that term then, but we handled McIntosh, Klipsch, Marantz, etc., so I guess we'd fit that description today). The owner was a good friend of Paul Klipsch and Paul would visit the shop from time to time. Mr. Klipsch was a pilot and owned a small private plane that he flew regularly. I’m told that instead of headphones to monitor radio transmissions, Paul preferred a midrange horn (or, squawker as he called it) out of or Klipschorn. I can imagine how loud that must have been to hear the radio over the engine noise! Considering that and his rather advanced age, I'm sure Paul had zip for high frequency hearing.
On one visit, Paul, and the rest of the crew at the shop were chatting and enjoying some tunes when Paul lept out of his chair shouting "Did you hear that? Play that part again!" We cued the cartridge back a bit and replayed the section, again with Paul exclaiming about what he'd heard - the rest of us struggling to perceive what he was describing. After several plays I could pick up a small amount of distortion that he heard immediately. Here I was - with pristine 18-year-old ears - struggling to hear the minutia that a gentleman approaching 70 picked out in an instant. It was a great lesson and taught me that "hearing" was more of a learned skill than an innate ability determined by physiological assets.
The subtleties that a high resolution system can deliver should not be thought of as exclusively high frequency events requiring bat-like ears to recognize, but rather a wide ranging sample of different aural attributes easily perceived and enjoyed by people with a broad range of hearing. Audophiles who’ve trained themselves to “listen” easily hear and appreciate the nuance that a high resolution system can offer. It does not require 20Hz - 20kHz hearing to appreciate and enjoy a high end audio system.