This article popped up a full-screen covering banner. Kind of makes the point. That kind of marketing actively makes me dislike you.
Also, as the article (hopefully) argues, "Marketing" encompasses a whole lot more than lead-gen and customer acquisition (two things pop-ups can help with).
all the popup does is confirm i was right to be leaving. its like letting the door hit me on the way out. also i accidentally trigger them while reading, and then sometimes leave.
If you have absolutely no interest in the product or service in the first place, then a pop-up is unlikely to change your mind. But if it's just that the deal wasn't good enough, this strategy can work.
There's a lot more to it than that.