If that were true there would be no new writers, because nobody paid them to write their first book. In fact, most first books don't sell at all. And yet... people write.
Not everyone is 100% motivated by money. And those that are do not all need full time employment doing that work. And those that need money and employment can often generate revenue with complementary goods. And those that can't can source subscription and other revenue sources.
The idea that the current model of commercialization of writing is the only one that has ever or could ever work is really narrow thinking. Writing has two main values: 1) the ideas, and 2) the expression. Both of those have put food on the table for good writers forever, and will continue to do so. The AI panic is just from people who can't imagine the world being any different than it is at this very instant.
Those positions become gated for the already rich. Only those who can afford to publish do. It's been this way throughout history. The internet changed this briefly but that may change. People are worried it will go back to what it was or worse.
Well there were eras before mass publication when some people still wrote, about science or history or whatever, either because they were funded by their religion or by personal money or by a rich benefactor. Of course it was a tiny % of people doing that, but then again it was only a tiny % who could learn to read and write or afford to spend time on hobbies.
