I can say from experience that becoming a self-employed artist is possible, but not easy or quick.
My path was to find a full-time job that used different parts of my brain from my art. I used my limited free time to brainstorm, create, and publish whatever I could make time for to slowly build an audience for about a decade.
Eventually enough folks discovered my work (and found themselves jobs themselves that allowed them more discretionary income) that becoming a self-employed artist became feasible for me.
Over three-quarters of my revenue is direct audience support like tips or Patreon. I make enough for my kid to have opportunities my parents couldn’t afford for me—while determining my own schedule and being more available to her day-to-day than my dad could be either.
I acknowledge it’s a gamble to buy supplies and spend time to make something, publish it, and travel to meet your audience a few times a year. I admit I’m lucky it paid off for me. But it isn’t as near impossible as the author makes it out to be.