Earlier quoted context omitted.
I have a blog no one knows about. If I’m trying to teach a concept or find something interesting I’ll write it up. The writing process itself acts as a check if I understand something. Then when people have similar questions/problems in the future I can just link. The personal value of the blog makes it worth trying at least.
I have tried it a couple of times (I do have a couple of posts on my github pages). I just don't have the time / motivation combination to do it on a regular basis. I find it quite time consuming writing in a way that makes it clear to others what I am doing. I'll come over to your computer and explain the same concepts in ten minutes that would take me an hour or two to write up and format in a manner that I would w…
I agree it's silly to expect every developer to have a blog. I strongly disagree with the only motivation for it being self marketing, or it being a somehow unreasonable question if you have one.