It seems like hearing-related diseases are generally poorly researched. For example, Meniere's disease (which is a vestibular apparatus disease, but also strongly affects inner ear due to them being very closely related): the cause is unknown, and the potential cure is only just going through testing phase. And even if it goes into mass production anytime soon, I still doubt I'll be able to get it.
I'd also say that the awareness of ear diseases in general is low. For example, I had no idea Meniere's disease exists to begin with, and once I've got it, I found out that there's no option to output mono sound to headphones nowadays (at least the wireless ones; I bet you can force mono sound into wired headphones with an appropriate adapter), which is greatly annoying.