The equivalent in writing for what most programmers do would be marketing, PR, journalism, or technical writing. You can get a paying job to write, it's just going to be that kind of writing - not for your Next Great American Novel. Likewise, I get paid a salary to bolt together shitty enterprise software and automate call-center workers out of jobs - not to tickle my fancy writing video games or exploring the corners of computer science.
Who needs a book about SVG? When I needed to build charts I took couple tutorials plus searched answers on stack overflow. It's way more efficient than reading huge book.
So, such books are needed by very small group of people. And this defines the pay.
> Who needs a book about SVG? When I needed to build charts I took couple tutorials plus searched answers on stack overflow.
The people out there who pride themselves into being able to do their work without relying on googling everything? What if you have an idea or a requirement that has never been done before?