WBIsMe
My first O'Reilly book sold 1000s of copies per month. My last book sold 5-15 copies per month. It took me 7 months working half time to write it. So, I was making at most $150 per month for the 2-3 year life of the book. I never earned out my advance, which was only $5,000.
Have you noticed? O'Reilly publishes few books anymore. You wonder why current books are garbage? Piracy killed book publishing, except for detective novels and other entertainment-oriented books that, in some sense, were garbage all along. So, you want free books? You got 'em. Just don't whine about how badly they suck. You wouldn't work for free and you can't reasonably expect capable authors to do so. They'll find something better to do with their time. Do I have to explain what that should tell you about those who continue to write???