Ad blockers are more sophisticated than that these days, or at least support features that are. For example, they can hide a specific DOM element on a web page

Ad blockers are more sophisticated than that these days, or at least support features that are. For example, they can hide a specific DOM element on a web page within a larger page according to its path or other characterization. I don't know what percentage of total effective rules these capabilities comprise, though, but it's something you cannot do with host level blocking alone.