I think that they missed something.
Culturally, I do not hear, "When are you going to write your symphony? Record your album? Paint your masterpiece? Pick your art. Nobody is asking if you will do this.
Publishing a novel is held differently. Culturally, it is held more fashionable than these other pursuits. Heck, by the sounds of it, publishing your own book is a cultural right of passage. The presumption is that you will do this. Where fashion goes, so does interest. Don't ask me why fashion went here. I do not know. Most likely, writing is seen as the art form most accessible.
In other forms of art, selling your own material is the expected modus operandi. If I am an artist selling my own prints, this is seen as natural. If I am a musician who recorded my own album, this is seen as ambitious. Yet, if I am a writer who publishes my own work this is viewed inherently as LESSER, and could even hinder my ability to get a publilshing contract.
Why is that? I don't know. That is a master's thesis, right there.
My current opinion is that we are now publishing more than the society can handle. While readership has been going down, the size of bookstores has been going up. Do I understand my facts correctly? That seems contradictory.
With this trend towards larger homes, are the book minded buying so many more books that they replace non-book minded?
The book market also has a feeling of "insiders" and "outsiders". People who know the system of publishing, and those who don't. That certainly contributes to the difference in arts. Any hint of "unprofessionalism" can lose you access. Going around that system to direct sales can lose you access.
Right now, there is a glut in people who want to get published, and that puts the power in the hands of the publishers. They can afford to be choosy. So come on back after somebody else took a risk on you, and I might take a risk, too.