Whenever the subject of software development books come up, a group folks jump in to talk about their absolute favorite books, and a lot of people hop in to talk about how books are no longer useful. They talk about how quickly they become out of date, or how they've become passé.
But from what I've observed, software developers are still very much into books. Book-related posts on dev.to always attract a lot of reads. When people post about books they want to recommend, so many developers click through to read.
When people talk about books, it's hard to know what inferences to make. People probably lie about how much they read because the ability to get through books is a positive trait or habit, like getting to the gym. Some might also follow along with the crowd in expressing how books are no longer relevant. So I can't say I'd really trust what people are saying, but I trust my observations that people click through and read posts about books at a great rate.
Click-through doesn't measure a whole lot, but it certainly implies an interest in the subject. Tweets from @ThePracticalDev about books get up to 7.5% click through, higher than just about any other posts, and they always perform above average. Clicking a link is also a private action. If someone clicks through to read something, they aren't sending social signals or being judged. Presumably this process is unadulterated by social pressures the way a public comments might be.
I would assume that physical books are steadily losing popularity in favor of e-books, but long-form writing in this space still attracts great interest. I've personally found the last couple software books I've finished to be of tremendous value, for what it's worth.