Anyone can write one book: even politicians do it. Starting a second book reveals an intention to be a professional writer.
I think the reason working-class people don't write books is because they are encouraged to believe that only certain people are permitted to write books.
In Mexico an air conditioner is called a politician because it makes a lot of noise but doesn't work very well.
Writers are frequently asked why they wrote their first book. A more interesting answer might come from asking them why they wrote their second one.