I dont understand your connection between the concept of intellectual property and understanding creativity in economic and quantifiable terms.
Maybe I’m unusual in my thinking in that I deal with the phases of creating a work and any economic potential of the work completely separately. I can ask myself “how many songs can I write/record/produce in X amount of time?” and quantify that, I can ask myself “How many units do I think this can sell and can I recoup my production investment?” or the dreaded “will my clients pay on time for the creative work I did for them?”. Those are distinctly economic questions but I don’t see that they are automatically related to “do I feel inspired to create today?”
Perhaps you mean in the sense that “If I don’t create some salable works today I can’t make rent and thus must efficiently monetize my creative output”? Of course we can understand salable in the sense of something people might want to buy or something which will attract eyeballs for advertisers. By this view I can understand your comment regarding fungibility.
