This is true and very unfortunate. My response to this is that when I want to learn anything in-depth, I use textbooks written by experts (e.g. professors, industry experts often from the past). It's hard to verify the expertise of blog authors and SO contributors unlike the authors, and blog posts can often be more about self-promotion than sharing deep insights. Sometimes I even write to these authors asking questions and they actually respond. To some extent, old internet is still alive and beautiful. It's just buried under a lot of noise.