I wrote a novel in the 90s and planned to self-publish it by printing it out at Kinko's and handing it out for free. Then I heard about one of those e-publishing ventures and did it that way. Big waste of money (I could have published it for free with them but I wanted my own cover so that upped the cost). Months after I did, a stock market fluctuation caused the company to increase the sale price, thus destroying any hope of selling them. It was a classic vanity press.
I talked to a Tor editor about my book at a conference and she volunteered to read it, but 6 months later she said what I had told her in the beginning, that it was probably not marketable (an Arabian Nights novel after 911).
Years later, I learned about Amazon and kindle and re-published it with them for nothing, and to my surprise, with zero marketing effort I sold several as kindles (I also did a paperback version but cannot be sure I sold any-maybe a couple). Unlike a classic vanity press, Amazon was interested in selling them to people and you benefit from the random ads and large number of visitors. I didn't sell a hundred, but I know others have sold enough to get an income so it is nothing to scoff at, vanity or not!
I could not care less about the vanity label. The stigma vaporized in an era of fake news and corporations.
I was conscious about it back in the early 2000s and I sent out untold numbers of short stories to magazines that had "pro" or "semi-pro" rates, but then I read an article by Stephen King where he discussed how the short story market was dying. In the 1950s an author could earn a living on short stories alone, but nowadays the pro rate was much less, and the editors tend to pick stories they liked, not because they were seeking to appeal to an audience.
And now it seems like everything has to be a series. Movies, tv, books.
I prefer "one shot" stories, so I wouldn't be marketable even if I tried.
But the corporate Wall Street-owned publishers are not writer or audience friendly anyway.
Big publishing is marketer and boardroom controlled, just as the film industry is. So if a reader or viewer wants something more old-fashioned, they have to look to online retailers.
One thing I have heard is you need 5 novels to have the quantity for a readership base. I only have 2.
When it comes to writing I am slower than molasses.