The writer's covenant.
Something to remember when you write:
You will play by the rules of the arena in which you write. If you write political thrillers, no magic. If you write journalism, no lies.
You will treat the readers with the respect due to someone paying your bills: you will not give anything less than your best.
Above all, you do not waste your reader's time; he is in a buyer's market of one, and you are only one thing he may read. Lose him, and he will never return.
Anyone who breaks the above rules and still sells is almost certainly literary, and thus exempt from the rules.
And somehow, while they are bought for coffeetable books, they will not be read for pleasure, which is the goal to begin with.