One notion that stood out for me in The Creative Habit was a section describing her frustration with trying to create narrative works of dance. Twyla Tharp is known for her abstract, conceptional dance pieces. At one point she tried to create works that had more of a sense of story and flow to them and found that she really struggled to create in that style. While reading Carl Kerenyi's Dionysos she was introduced to the Greek concepts of zoe, which deals with the whole world (it is a root of the word zoology) and bios, which deals with individual narrative stories (a root of biography). She came to the conclusion that she works well in the more abstract, global zoe style but really didn't have a knack for dealing with the bios. Emily Shur appears to express a similar concern, that everyone tells her that she should be working on photographic projects as the way to grow, but her mind just doesn't work that way. She'd much rather explore the whole world and find the pieces that interest her, rather than settle in to focus on a bios narrative photo-essay. She seems to be finding gallery representation or acceptance difficult as a result because everyone wants to see projects presented in the bios mode of creation, while her approach is looking at the whole zoe.
I've noticed this myself if you look at artworks in a coffee store - those typically aren't the result of an Art world selection process and often display an ecclectic, disconnected mix of images, photographs or paintings. Often the greatest hits of the particular artist selected to display images (or who asked the cafe owner first). It is unusual to see any cohesive story or message in those images, other than the common creator of the work. Art gallery shows are almost always in the bios mode of a cohesive body of work on a particular theme or topic. Still often the same creator for all the images, but a much more heavily edited and selected body of work.
Perhaps some people are just wired to look at the whole rather than pull out individual stories and follow them. That's just how their creative DNA is. Projects and themes just might not be right for them as a means to creating great photographs and they could embrace that, rather than always feeling jealous or frustrated.