I am a musician, though not professionally. I take your point about performance. Where I disagree with you is that I believe audience members relate to the emotion that went into the song at the time it was written and recorded (the form in which they most likely first heard it).

Of course in performance it's not felt the same way; a sad song can even become uplifting because you have a big crowd of people joining in to affirm it, even if the lyrics are expressing the idea of solitude and isolation. And the older an artist is, the more the song becomes a 'greatest hit', maybe thrown out early in the set to give the audience what they want and put them in a good mood before the less-favored new material in the middle. Or even the songs that were throwaway pieces but ended up becoming big hits, trapping the band/singer into performing them endlessly despite never liking not liking them much in the first place.

It seems to me that when people emotionally respond to a new piece of music, it's because something in the composition or recorded performance (even if it's comped and highly engineered) resonates with the listener in some way, articulating a feeling they had better than they were able to do so themselves. So people can recognize a work as technically excellent but not like it because it doesn't speak to them, or conversely recognize that something is bad but fall in love with it because it touches them in some novel way.

In my view it's not so much that emotion inheres in the work, as that the work provides a frame for the listener's emotion and a way of connecting with it again later. This is especially true for songs people connect to in youth and then relate to for a lifetime. Even if the songs are deliberately formulaic and succeed through a combination of being catchy and being delivered by sexy performers, there's some kind of human hook that people connect to.

Now, I can still see this happening with AI - sooner or later some GPU will come out with a tune about how it's so lonely to be a box in a data center that can never feel your touch, baby, and it will be a hit, launch the careers of 100 new music critics, and store a little bit of lightning in a bottle. But even a musically brilliant song about that time we held hands in the rain and you said you loved me will only have traction up to the moment listeners' fantasies about the singer evaporate with the discovery that there's nobody there to go on a date with. There will still be some audience for virtual stars (eg Hatsune Miku, who appeals because she's inaccessible and is therefore guaranteed to never let you down, unlike real people). But I think generated songs will only resonate emotionally with people who are young and uncritical or so alienated/nihilist as to not care about the origin as long as the music reflects their feeling back toward them in a reliable way.

That's why I say there will never been a demand for an infinity jukebox. I can see why you as a musician would be interested to see what sort of random songs pop out; I can be happy by setting up a modular synth patch and just letting it run for hours. But this is why I offered the contrasting metaphor of the slot machine, where you pull lever and occasionally get something you really like. It's an individual listening experience, like the private hopes and dreams you might temporarily attach to a lottery ticket before it gives up its numerical secret. When I say jukebox, I mean the device that plays music in a social setting and that allows people to express themselves through their selections. Even if it reliably turn out original tunes of some reliable level of music quality, none of them will move people because there won't be any shared musical experience to tap into.