Even if you is selfhost google, facebook & co still have a big influence over the traffic you receive, so alhorithm changes still affect you.

For a book, other ways of advertising are effective, so you're reasonably independent. For news and other small pieces of content, it's much harder to avoid dependence on big aggregators.

The difference is that you’ve effectively created one piece of content - a big book on dev ops - that will be very interesting to a small set of people. People can visit, decide they like what they see, read a bit, bookmark, come back later and read a bit more and perhaps pay for the paywall stuff. LittleThings is creating lots of articles slightly interesting to a larger set of people that requires a constant stream of new viewers - because people appear to not come back voluntarily unless they see a new interesting article in their Facebook feed.