Professor Fuchs did a webinar back in January on the ear, hearing, and upcoming treatments for hearing loss. He talks a bit about genetic deafness and how gene therapy can address it. He also seems pretty positive about hair cell regeneration as being a thing. I just skimmed through it, but looks really informative.
How the Ear Hears, and What We Can Do About It
How the Ear Hears, and What We Can Do About It