Every book that is published is first judged worthy of publication. No one can survive if many books are remaindered. A certain number of hit titles are required. These books sell and are then reprinted, and continue to be reprinted.
Any publisher who blames the author is blaming the wrong person. It is the job of the publisher, if he wishes to last beyond year number two, to make good choices. To release books that the target audience will like.
It is the publisher's job to pick that appealing title, to look over the contents with an expert eye and to get the word out.
Finally, I have had much more trouble with writers compared to artists. While authoring the text is a lot of work, authors don't pick titles or suggest artists or make final layout decisions. Lately, I have seen a number of military history titles that are too wordy or too vague or both. The average buyer scans the shelves and needs some eye-catching wording that immediately conveys the contents. My favorite big fail is The Oranges are Sweet. Which is fine if it's for your comrades but unlikely to be a hit among the public. That's not the only example.
As far as cover art, an art director is required. Authors are not art directors. I have seen some really bad covers in the aviation history area lately. It leads me to assume that someone with no knowledge of what makes a good illustration was involved. Along with the title, the art helps to sell the book. Get that wrong and some may not buy.
