Hearing loss usually occurs over a long period of time and the brain is very good at getting used to something that happens very slowly. If you had normal hearing and went to bed one night and woke up with the hearing that you have now you would feel as if you had gone partially deaf. People who loose their hearing suddenly are extremely uncomfortable and seek care right away.
Imagine if we’re talking about your vision and 15 years ago you went to live in a cave illuminated by a 150 watt lightbulb. Now imagine if every day that lightbulb intensity was slowly turned down, so slowly you wouldn’t notice it, to the point where it now is a 20 watt bulb. You would still feel as if you could “see“, however, you would be missing the crispness and clarity in your vision, not seeing the vibrancy and the intensity of things around you that you once did with the 150 watt light. That is the same thing that happens with your ears over time and although you can “hear“ you are missing the clarity and crispness of sound.