The material is rivalrous, the pattern isn’t.
The copy is rivalrous, the song isn’t.

Even on a hard drive or in RAM, users of the copy have to take turns.

Well, ok, it’s theoretically possible that simultaneous concurrent access to the same media can be contrived, but when people talk of copies it’s invariably in the rivalrous sense. My copy, your copy.

Anyway, bar that weeny gripe of mine, you are right to observe that the value of a song increases the more it’s copied. After all, who gives a fig how much the copies decrease in value? Except those who manufacture and sell them…