At the very least, for this argument to be true you would have to rewrite the syllabus to focus on problem-solving rather than knowledge. But even then, there is no compelling reason for having this particular way of teaching skills, and little reason why other subjects should not be teaching the same kinds of questions. Given that it is hard, not related to the real world and generally unpopular, we should drop it. Instead, design other classes, with “being engaging” specifically in mind. This will do a better job.