And yet we're paid to write derivative songs all day which is why I don't think the analogy fits.
If I write yet another rails app that does nothing to push the industry forward and isn't novel (to a computer scientist) it nonetheless provides business value. And since it isn't consumed on use it's clear that we're talking about a bespoke durable good — a chair, a shelf, a thing that is useful without it being novel.
Software might be made of words but that doesn't make it a recipe or a song.
But in this case, the bespoke rails app does do something that other ones do not, in the sense of it works with a specific database with specific operations.
To stretch the analogy, "this chair fits people who are 180.3cm tall better than any previous chair"
You're comparing completely different products by abstract concepts that are entirely contextual. So the GP is going to be just as "correct" as you. That's the problem with analogies, the more abstract they are, the more people disagree because they perceive them from a different contextual view point.