It's worth being very clear about the reasons for it. You say you're not trying to build a media business, and want to build a "public notebook", but you imply you're looking for career/networking opportunities. You're also not clear if the "learning" is for you as the author, or for the reader.

If you want to have your content discovered online, I'd say you might be in for some trouble, although I don't think AI is the cause, only an accelerator on that. Blogs for readers learning are probably in decline, you're unlikely to get any outreach based on your posts for networking.

However if, like me, the writing process is the point – you're trying to clarify your thoughts, learn something new yourself, or have a document you can share with colleagues when they ask you to explain your opinions, I think blogging is valuable. While you won't get direct outreach, you can share it on your CV or send it to recruiters and you might get noticed when applying for jobs.