There’s a big difference between a necessary and sufficient condition—aka, Two-Factor Theory. From Wikipedia:
The two-factor theory (also known as Herzberg’s motivation-hygiene theory and dual-factor theory) states that there are certain factors in the workplace that cause job satisfaction, while a separate set of factors cause dissatisfaction. It was developed by Frederick Herzberg, a psychologist, who theorized that job satisfaction and job dissatisfaction act independently of each other.
Make no mistake: The same principle applies to a book’s cover.
A great book cover doesn’t guarantee success. A horrible cover, however, will virtually ensure that your book goes nowhere.
What’s more, it doesn’t matter if we’re talking about virtual or brick-and-mortar book stores. An ugly, messy, or overly busy cover is going to minimize your book’s impact regardless of where it’s being sold. Period. If you get one thing right with your book, make it the cover.
What say you?