There was (and still somewhat is) a big uproar about auto tune usage in music. But guess what? You haven’t heard a song NOT using it since at least 1998. Unless youre friends with every sound engineer out there and can ask them specifically if an artist did or did not use it (unrealistic).
The same will happen with ai. People wont notice, and it will go on to be the norm, with a very small pocket of purists.
I have a very hard time believing that, unless of course sound engineers have been doing “manual-tune” for ages and ages (see below). Regardless, loads of singers who perform in front of others clearly have the ability to sing a song in a variety of ways depending on mood, venue, audience, occasion, etc. In short-- good singers REALLY ARE that talented, generally with excellent pitch, and don’t need assistance in something as basic as singing notes close enough to pitch-perfect without the need to be absolutely perfect.
Just look at how improv singers can do so well, or people performing in front of judges, or opera and opera-style singers performing in concert halls, like Charlotte Church.
I would guess the one argument of yours that holds some water is with flawed singers who are otherwise good, but have chronic problems hitting close-enough pitch, or really good singers trying to perform songs slightly outside of their range. Stuff like that…