theory of the hack: What makes an artist a "hack"?

I loved this post by author Emily Zhou about what literary hackdom is; how to identify it as a different thing than merely being a "bad artist"; and what hackdom tells us about it's opposite, which is genius:

1. "The hack is not the same thing as a bad artist or a writer, or someone who makes what they know to be bad work for money. The hack is something else, a social as well as artistic type that has existed since the beginning of capitalism, at least. Plenty of people seem to know a hack when they see one; fewer notice that any individual artist or writer worthy of the name has siblings everywhere, whose work shares certain aesthetic qualities and whose personalities are congruent with each other."

"6. The unstoppable confidence of the hack, which hinders their improvement, is phenomenologically indistinguishable from the confidence, the fluency, that true geniuses have. One imagines the inner lives of Bach or Balzac had certain things in common with those of the hack.

1. One is tempted to say, “but not those of Beethoven or Kafka.” But it does not matter whether any individual hack struggles mightily to produce their work, or is crucified daily with self-doubt. The trouble is in their taste: the standards used to evaluate the work have seemingly been calibrated incorrectly. They have climbed some alien Parnassus to get to their mediocrity, and usually have stopped early and declared that they are on the peak."

What are your encounters with hacks like? How can you tell when you've met a real one?