-Before the internet, space to publish anything was scarce (and so were methods of finding specific information if it did exist), so newspapers/magazines were valuable and textbooks/guides were great media.
It was difficult to find extremely specific information because a lot of information was so niche it wasn't worth publishing, or because it wasn't worth the effort to find something SO specific.
-The internet made publishing space infinite and search easy, so specific information became super valuable, e.g. "how to do x in 5 steps" blogs. They architected information in ways that wouldn't have been worth publishing in a regional newspaper or small-circulation magazine, but was economically viable at worldwide scale and when publishing was free.
This is the era this article describes.
-Then everything went mainstream and the above production of content was often more frequently done by large companies, with bloggers and other individuals filling even smaller niches
-Now that LLMs have vacuumed all of that up and you can create even more specific content for free, instantly (e.g. you no longer need a generic tutorial on "how to start a business" but summon one that already knows your prior skills etc.)
This has made the previous era of "how-to" content less useful because you can decide whether you want expert/beginner/intermediate level content and what personality etc.)
Now the frontier is first-person narratives and opinions, because even specific information is no longer the constraint.