Alex, I like the overall idea behind this article, but I think your title (“How Can Art Exist Inside An Age Of Digital Content?”) is incorrect. You’re not really talking about “Art” per se, you’re talking more about the “creative process”.
In a free form creative process (painting, etc), the artist really has no idea as to what the final piece will look like or how it might be used, or perceived. They might start out with some initial sketches or ideas. But if they are true to the process, they will remain flexible enough to “go with the flow” in terms of where that process is taking them.
If an “artist” is are more interested in creating a specific product or image, then it’s an entirely different creative process. There are different processes involved for different outcomes, one size does not fit all. Filmmakers start out with a script and storyboard, sculptors begin with a sketch, writers will have an outline, etc, etc.
Designers on the other hand are much more definite about what the end result will be. Are they creating “art”? Well, that’s one for the art world to decide, not the creator.