Comment by biztos
Additional factors that come to mind: the slow realization that you could be writing for an audience of one (yourself) after a brief surge of "famous bloggers"; and the rise of other forms of writing (social media, etc) that at least give you the illusion of an immediate audience. "Engagement metrics" and so on -- even if they represent the opposite of attention.
I think a lot of what used to go onto blogs now goes elsewhere, but doesn't necessarily stay bottled up in the mind of the would-have-been blogger. Even while pseudo-blogging platforms like Substack are having something of an upswing of esoteric low-audience content.
And I can say from experience that it's tough keeping a blog going when you have near-zero readership, even if you still consider the act of writing something and putting it out in public to be instrinsically valuable to you.
Just as a simple example, I have a once-in-a-while newsletter+blog on a niche topic, and I could get way more eyeballs if I'd just rephrase things as a Reddit post, but I'm nostalgic about it living its own life on the Free-ish Web. Or, I suppose, this comment right here, which could just as well be on a personal blog with a "backlink" to yours.
>I think a lot of what used to go onto blogs now goes elsewhere
That's been true of me. A paragraph or three that I would once have done as a blog now slip neatly and easily into social media of various sorts. Going to try to do something about that next year but this year ended up crazy for various reasons.