It's just such a tough discussion, because it seems to me that to debate or to consider a"cure", you have to define deafness around the function of the damaged portion of the ear, when as you pointed out, deafness also impacts the way the brain develops. Which means that repairing a few hair cells or transplanting entirely new cochlea, or taking a magic pill to cure the damage to the ear will have no effect on what's already changed in the brain. And those changes occur so rapidly in little ones. So, a cure may not result in much change for many deaf.
I read one MRI-driven neurological study that showed that without hearing, that physical location in the brain previously assigned to language (spoken and written) was taken over by sense of smell -- and flashed on the MRI when smells were being triggered rather than when conversing or writing. I've asked our surgeon if they know whether or not CI kids reallocate this part of the brain to spoken language or if yet another bit of brain matter real estate is being commandeered for the newly acquired sense of hearing. He didn't think that had yet been studied.