The truth is that most short story publishers pay about 3-10 cents per word, so the pay for your work is usually less than $300-500. Most novels sell less than 1000 copies, and often far less; even then, the author might only get 10% of the price tag unless they self publish (but then sales are apparently 1/10 as high)
If you earned half minimum wage, you would have cause to celebrate!
Even authors of bestsellers often have day jobs unless they have a string of huge successes. That’s why we see so many sequels — less risk to the author who sees their chance to finally be a full time writer
There are so many sites out there right now hosting free fiction that it’s hard for many to find readers, even if the work is released for free. Many authors I know spend more time on self promotion than in writing due to this: otherwise, nobody will ever read their work in the first place
Publishers are now preferring authors who already have large followings, which reinforces this dynamic
For some people, writing is a vocation, but for 99.999% of the others, it’s a dream or a hobby, or a way to meet like minded people and enjoy being part of a community
Anyway: go out and read some small publisher books. Many are fantastic! There are a stunning number of great books around with 0-3 reviews that never had a shot — look for them sometime!