I think formats are better suited to express certain types of ideas than others ("the medium is the message"). Blogposts tend to be ideal to express fairly short, singular ideas. Books should develop an entire thought system and connect various ideas, which take much longer, both in producing and consuming. The range of what you can express is also much more expanded, since you need the person to be in the right state of mind to understand or accept an idea; with a book, you can slowly lead them to that state.

Compared to a few years ago, I don't remotely have the same enthusiasm I could have for blogposts, and on the contrary I often find the writing style to be irritating -- especially hyperlinks-rich ones, which break the flow of thought, like internalized distractions. Yet I've also started to write my own blogposts because there are some ideas that I wanted to express in that form and did not find on the internet.

My guess, based on my own experience: you have reaped what you could from the ideas that can conveniently be expressed in blogposts, and it would be very hard to find new ones that would enrich your worldview. You have to go deeper, thus find the format that is more suitable for this.