[ralfd]

That is an apples to oranges comparison. An article about a video/book would have the relevant information in text form without needing to show the video "here is the new stuff shown in Apples 2 hour long WWDC keynote". If not is common that a comment in the discussion gives a summary as a tl;dr

With text articles behind paywalls the relevant information is hidden and only hinted at as a teaser.

[munchinator]

To make it an apples to apples comparison, look at submissions where the link submitted is the retail link to the IP. For example, look at all the book link submissions on AMZN...

https://news.ycombinator.com/from?site=amazon.com

None of these have the Pirate Bay or Library Genesis or Anna's Archive or the equivalent as the top comment.

Compare that to...

https://news.ycombinator.com/from?site=nytimes.com

And almost all of these have an archived version as the top comment.

[tmhrtly]

I wonder if this is because the purpose of linking to a book is to share awareness of that book’s existence - nobody is about to go and read it then and there to comment on its contents. Whereas the purpose of an article is to discuss it now, in the comments - the consumption horizon and bulk of the content is different.