That’s anybody, really. Everything you’ve ever accomplished has depended upon the insights and knowledge of countless other people who never saw a dime from you for it. That’s part of living in a society and it’s a crucial part of how it advances.

Yes, that is why I phrased it as I did.

I agree that art is a form of communication, but it’s also a source of inspiration regardless of the artist’s intent. A person can derive meaning that the artist never intended. So I wouldn’t say art is totally a subset of communication.

most of the value we get from creativity isn’t from the mechanics of creating something

This part I would disagree with. I think 99.999% of all art is created solely for the creator’s benefit. The other 0.00001% of art is hanging on display in museums, etc. In the case of creating music, the playing of the instrument is very important to the fulfillment of most musicians. And learning the mechanics of painting, or sculpting, etc., is where I think most of the value of most art comes from. The mechanism of creating art IS the act of communication; it’s channeling thoughts and feelings into something tangible. You likely had an art class in school, not because they wanted you to create something you could sell, or to learn a skill that was going to pay the bills, but because the act of creating art is fulfilling to the creator.

I think this is part of why Sand Mandalas are destroyed after they are finished being created. It’s not the existence of the piece that is important, it was the creation of it.