Recorded music just like isn't a commodity. It's not close.
In fact, if you took a spectrum of all mass consumer products and ranked them from most like a commodity to least like a commodity recorded music would probably be on the side of least like a commodity.
It's not really an argument. Recorded music is not "kind of like" a commodity. There are tens of millions of recorded songs and literally every different iteration is wildly different, people consider some of them literal core elements of what gives their life meaning while other examples of the exact same product they have a visceral and intense hatred for.
We have a basic disagreement on facts here. My experience of the world is that very few songs have any substantial difference from the world as 1,000 other songs. With a small number of songs having the properties you describe. They are different in the way the patterns on the skin of an apple are different. Utterly unique, but not in a way that matters to consumers.
Diamonds are, perhaps, a good analogy here. Diamonds below a certain carat size are a commodity. They're ground up by the ton and sold for use in a variety of products at a cheap price (category 1 songs). Larger diamonds are not a commodity - a 45 carat diamond might be considered a national treasure (category 2 songs).