That's why we have the disability / impairment distinction. Many impairments don't have to be disabilities. Some are, inherently.

I'd argue that deafness can be completely mitigated by societal improvements, for most purposes except birdsong etc. and certain genres of music. Blindness is more difficult (e.g. vision is useful for navigation, and we can't choose the surfaces in a forest to make echolocation easier), but in principle computer technology can help with that. (I'd say a decent automated audio description is still a hundred years out, but we'll only get it if we make progress.) Certain mental impairments (e.g. some depression, some sensory issues) have no known mitigations, even in theory, so remain disabilities in all circumstances.

You're focusing on mechanical issues and ignoring social issues. You mention birdsong, and certain genres of music... what about your partner's voice? Your child's laugh?

I count those in the same category as birdsong. You can see, and/or feel, laughter. There's an equivalent to "voice" in every mode of communication I'm aware of (speech, sign, romantic chess, oil-on-canvas…). There's the inherent disability of not being able to access those modes of sensory experience (and I'm not belittling anybody's desire to experience them who can't) but the social impact of the impairment is incidental and avoidable.

Perhaps these things are culturally significant, above and beyond their inherent social value, but that isn't intrinsic or necessary.

> even in an ideal society, being, for example, blind, or deaf, would still be very difficult

Correct. The technological model OP posited would involve technologies that let blind and deaf folks navigate the world. The social model hits a barrier at that point.

Sure, but then there's other conditions that for a lot of people are basically entirely social. E.g. ADHD. Having a fulfilling life with ADHD is pretty easy. Holding down a job to pay for that life less so.