What you say is "marketing," I think is author creativity.
What's the difference? Just because the author wrote the title doesn't mean it wasn't chosen for marketing purposes -- to grab your eye, to be memorable, to describe the subject concisely, to pique your curiosity, to remind you of a story inside of the book so that hearing the title mentioned in conversation prompts you to tell the story. Authors are marketers too. Indeed, the first task of any new commercial author is to convince a publisher to buy a manuscript, and that requires a title which catches the publisher's eye, and which the publisher is convinced will catch the public's eye.
In other words, when I suggest that publishers pick titles with an eye to marketability, I'm not suggesting that the typical model is "publisher buys the book and then suggests the title". I suspect that's actually rather rare, although some authors have had that experience. Much more likely is the model where the publisher solicits hundreds of manuscripts and proposals and then picks out the handful that feel commercially viable -- and a good title helps a manuscript to stand above the rest of that slushpile.
What's the difference? Just because the author wrote the title doesn't mean it wasn't chosen for marketing purposes -- to grab your eye, to be memorable, to describe the subject concisely, to pique your curiosity, to remind you of a story inside of the book so that hearing the title mentioned in conversation prompts you to tell the story. Authors are marketers too. Indeed, the first task of any new commercial author is to convince a publisher to buy a manuscript, and that requires a title which catches the publisher's eye, and which the publisher is convinced will catch the public's eye.
In other words, when I suggest that publishers pick titles with an eye to marketability, I'm not suggesting that the typical model is "publisher buys the book and then suggests the title". I suspect that's actually rather rare, although some authors have had that experience. Much more likely is the model where the publisher solicits hundreds of manuscripts and proposals and then picks out the handful that feel commercially viable -- and a good title helps a manuscript to stand above the rest of that slushpile.