There are some good thoughts in there, but it fails to answer the actual question. Why publish a blog? Sure, writing has benefits. You don't need a blog to write. You don't need a blog to make your own content linkable.
The only nuggets in there are "vanity", "monetization" and "possible opportunities" which are all pretty bad reasons to publish a blog.
Sharing knowledge doesn't require sharing publicly? You seem to be looking at blogging exclusively as a vanity/recognition thing. Meanwhile, I've come across numerous blogs that have helped me solve a problem. I don't remember most of their names, but it's the kind of thing where I'll recognize the website if I need to search for the solution again.
The only nuggets in there are "vanity", "monetization" and "possible opportunities" which are all pretty bad reasons to publish a blog.