That’s not the only factor. Their publisher also decided there wasn’t a market for a book and declined to publish. The author also didn’t say Julia was a dead language, it just failed to realize the dream of becoming the language, and is instead just a language in a sea of many.
"Post-mortem" doesn't imply that it's dead? And also, of course there isn't a mass market for a book on a programming language that's not python and due to most learning material being available online. This is a stupid metric.
The title doesn't and can't contain all the nuance of the article. Considering that books were published about data analysis in Clojure, the bar to clear for market size isn't that high. A lot of people buy books for reference even when you could learn everything online.
They might have been published, but how successful are they? I have no idea, but it's very realistic that one publisher is more risk averse while another isn't. This doesn't say anything about the language, really.
