I would argue that clough42 does fit a niche where all the videos are on a topic, in his case it's doing very ambitious projects/modifications that the average

I would argue that clough42 does fit a niche where all the videos are on a topic, in his case it's doing very ambitious projects/modifications that the average home-shop person wouldn't attempt. Another example would be nighthawkinlight, who does a wide range of projects but with a strong home-shop/diy science bent. If either of these channels started posting stuff like cooking or video essays, I would potentially unsubscribe. Those are both things that I also subscribe to, but having the different things all on one channel makes it too unpredictable what kind of content I'll be clicking on. For a blog, many of the same rules apply. A blog relies on more external links into the content than a YouTube channel, but you still want a consistent theme. If I click a blog from here or another site, if the content is good I'm likely to read other articles and either bookmark/rss/subscribe via email. If the articles are a mishmash of topics, then I'm less likely to want to engage further since I don't know what I'll be getting. And you want that dedicated core group for a blog to be successful, since those people are the ones who will start posting links to your stuff on other sites. An example from HN that comes to mind is brr.fyi, I know I'm not the only person who subscribed to his email notifications, since everytime I've gotten an email I've also seen the article posted to HN, so other people have been following and have been faster at posting the new article as a HN story than me.