Because if you look at any picture objectively, you think "Anyone could do that", which is why a lot of people pull up their noses at art, and by extension, anyone pursuing a career as an artist.
But art where the process is part of it is just one of the many branches of the art world. A lot of people consume the arts on a regular basis without even considering it. UX is part of it, TV shows, films, video games, basically all media is an expression of art and will have a small army of artists working on them.
Hand-injected and machine-injected history of a given bubble may not be a distinguishable property within the natural universe, but it's important to art collectors, in a similar way that the copyrighted or not-copyrighted status of bits gives them an invisible color to lawyers: https://ansuz.sooke.bc.ca/entry/23
A cool hacker project would be to make a “bubble printer” with an automatic injector that given an image will try to reproduce it in bubble wrap.