This post feels misleading or possibly just nostalgic. The books referenced still exist because the people creating the technology are still writing them. They're also creating video and attending conferences (virtual or otherwise). That's not going away anytime soon. But perhaps what has changed is how the information is accessed.

Do you need to debug some ancient perl? Sure, ask Claude. You'll get an answer and move on. But if you're looking to learn how to use the next technology before it's mainstream, you'll go looking for that material. And it's there, where you expect it to be. Do you still watch network television or haunt Blockbuster? Times change and the market moves on. The interesting thing is, people like books and they're also available for those looking for a physical artifact to hold. Most of what's available is POD. Depending on the title, you're hitting the print button when you place the order.