While authoring a text book takes skill and practice, it is a process. The same could be said of a Brittany Spears album. They are carefully crafted to appeal to a wide audience.

Art serves no one other than the creator. Try to tell Picasso realism is more popular, or Charles Bukowski that he needs to tone it down. Not gonna happen. Because they weren't doing it for money, but simply for the pleasure of doing it - living; satisfying that itch to create something exactly as they wanted to.

Obviously, sometimes artists happen to strike a chord with society. Their vision becomes mainstream, their work becomes collectible, lots of money trades hands. But this didn't happen because an editor said "Bukowski, go write something these damn hippies will like and I'll pay you $$$"

More often, an artist strikes a chord with a few people. They make a little money. They keep their day job. Maybe they get a grant.

Why would a publisher pay an artist to create a work? What does the publisher need it for? The answer: to sell it. How can the publisher profit from this arrangement? Without the exclusive right to that work (i.e. copyright), they can't.