They also itch in winter. And monks don't have sex. I'll stick to the world. There are loads of authors marketed like breakfast cereals whom I refuse to read because I've found them even less nourishing than Frosted Flakes. But there is something important here for young writers to understand.
Writing is a business.
No different in that respect than what Kellogg's does. And anyone who wants to earn a living at writing needs to understand the business of writing. I can tell you that each new book gets harder to do than the one before. It now takes me all day to do what I used to do all day.