It's like saying "you can make money on Kalshi." Not false, but reductive.
I know plenty of authors, self-publishers and traditionally published, who've lost five and six figures marketing their own books. Whether this is worth doing is subjective, but for most people, it's not.
You are literally responding to
> I really don't know if it'll have an audience
No amount of marketing can help you out is your entire market is shrinking daily. Shriking markets are also not won by quality. The more competition, the more marketing then becomes the main thing, and you also need to alter the book in the process so that it fits the bite-sized pills you can push on most channels, or worse change it so much for the audience until it becomes something else entirely.
The worsening health of the market is a real issue. And yes, writing to market is a grind. Writing for virality is worse, because you compromise the work and also don't get anything for it most of the time.
----
[1] Own-buys are common with business books. You take a loss, but you get a promotion or you earn speaking fees from the status of being a bestseller, even if no one read the damn thing. For literature, they'll cost you more than they're worth—you'll get a better advance, but not as much as you paid for the bestseller distinction.
And that's precisely the issue here. For a while, the internet allowed you to find an audience, just like that. Start a blog / podcast / YT channel, keep going, get enough attention. You could then approach a traditional publisher and tell them "hey, I'm kind of a big deal", or you could self-publish and rely on the word-of-mouth from your followers.
Now, how would that work? If you have a blog, AI answers will summarize it without attribution and not send anyone your way. Even the "references" cited in AI answers often point to AI-slop blogs, not the original source. The articles we discuss on HN are often AI-written too. So yeah, it's about reaching the audience, but you're now competing with machines that produce an endless stream of human-like text, good enough for most consumers, practically for free.
A book won’t sell itself.
Which addresses your second point: machines can produce an endless stream of human-like text, but they have exactly the same problem as human generated text: finding an audience.
How are these endless streams of human-like text finding an audience? Most of the time they are not.
And as soon as you scratch beneath the surface there is no one to interview. No one to turn up at literary festivals. No one to write opinion pieces or blog pieces for book-interested audiences. As I said: writing isn’t the problem. Finding the audience is the problem.
What distinguishes a book that is read by no one from a book that is read by a bunch of people? It’s definitely not the writing. There are great books out there that never find an audience because no one ever went out there to find an audience for those books.