I make a living selling iOS development courses at high prices, so I can tell you that the we didn't lose the paid ecosystem.

I can't talk about book publishers like O'Really, and probably the market for books shrank. But I have several competitors that sell self published ebooks.

The plethora of free content you find online is not always a good thing for everyone. As the author of the article says, most tech content is bullshit. Most people don't care, but there are plenty of people that realize that and are willing to pay.