I feel like the author is smuggling in an ill-defined notion of what makes someone a "writer". I've played the piano since I was three, but don't get paid for it: am I "a pianist who got paid $0"? I also took a one-off front-end engineering contract once: should I be shifting the statistics of what the median front-end engineer makes for every year that I don't work in frontend?
Fundamentally, the author is describing a fulfilling hobby that pays a partial income, and bemoaning the fact that it doesn't guarantee a full career. I'm not unsympathetic to where she's coming from; the reason I'm a longtime supporter of UBI is because I think that things like the ability to engage in arts and hobbies should be supported at a baseline for every citizen. But this article somehow casts writers as uniquely poorly off, ignoring all the people who would love to do any of a number of hobbies full-time but have career paths that are far more limited.