No matter whether they consider themselves disabled or not, hearing > not hearing, and anything they could do while deaf can still be done with 100% hearing restored.
I think you're imagining CIs as shiny and perfect technology, but they aren't. Check out this article below for some details. [1] They take quite a long time to learn how to use. Also, for people born deaf, their hearing isn't restored, it never existed, so it becomes an addition and an added responsibility. It's two new skills - hearing and speech therapy - they have to learn since ASL/etc is already their first language. It's really just a random cultural conditioning that we tend to think we have to be perfect or even enhanced to have a good life, be loved, successful, etc., but there's much more to life than the hearing world.
> hearing > not hearing
Actually, it turns out "not hearing == hearing." They make friends, make money, program, cook, play sports, exercise, etc. You might say they can't do this with people who aren't deaf, so they have a smaller population to choose from, but their community is huge and well-connected. they actually don't need the rest of us. I sat next to a deaf guy on a plane and he ordered coffee with cream and sugar by typing on his iphone then read the whole plane ride.
[1] https://www.thisisinsider.com/why-deaf-people-turn-down-coch...
It is unrealistic to suggest that most deaf people would refuse an operation to have their hearing restored. This is just as crass as suggesting that someone who has learned to live a full life with a prosthetic leg would turn down the (hypothetical, futuristic) opportunity to have a brand new biological leg...
As it turns out, there were quite many people who actually did not prefer modern civilization and especially the forced nature of it, and we now look back on those attempts as hallmarks of an embarrassingly racist era.
History suggests that we should be cautious of assuming that others share the same values we do, especially if we have never experienced the world in the same way as the other person. One thing you can't do with 100% hearing restored, for example, is enjoy true silence.