I think its just the way we use our senses. Take a look at the average guy, which of our senses do we use the most? If we have even the slightest problem with our eyes, what do we do? We get glasses, we get contacts, now we even get surgery. If your vision gets a little blurry you worry. If your hearing is diminished, more often than not, you dont notice it at all. And the average guy doesn't give a damn until their hearing is gone. As far as we're concerned, as long as we can hear its fine, its not a medical issue, its not a big deal, its just "hey can you speak a little louder?" And then if we begin to really lose our hearing, we get hearing aides. But then again do we care about Sound quality of hearing aides? NO, not one bit, as long as we can hear other people.
Just ask anyone when's the last time they went to an ear specialist about their hearing? And then ask them when's the last time they got their eyes checked? And even when we go through tests for our hearing, we are tested for our ability to "hear something" not how detailed it is. On the other hand, our eyes get tested for clarity, resolution, and whatever else that eye chart test does. Then we get custom fitted instruments (glasses/contacts) so that we can get "perfect vision." Now ... wheres the audiologist that could do that for me.
At the end of the day, our hearing is pretty much at the bottom of the food chain
Our eyes get checked as soon as we notice something weird
Then our sense of touch when we can't feel something (cuz that's usually a big issue)
Then our sense of smell and taste (these go hand in hand) and usually its when we get a cold. Notice that when we get a cold, our hearing is also impaired but we normally dont' complain about it
And then there's our hearing-the sense that we could careless about until its gone.
But yeah unless you've been brought up on classical music, gone through music lessons, and really developed your ears... you're not using your ears to your full potential, and if you've gone to concerts... well you may never get to use them to their full potential.