I can appreciate that it makes little sense to hire a person whose sole job / title is "prompt engineer", but there is a tremendous amount of knowledge embedded within the many valuable prompt frameworks that guide GPSs to not make their own assumptions. Underlying hidden assumptions, context and purpose are not something that can be magically extracted from a users head, and in person to person communications are deep and unspoken. Further, it would violate Grice's Maxims for a chat bot to hound a user about context and purpose with every new prompt or otherwise train the user to ask good questions. It makes sense for GPTs to make a best guess and often guess wrong when the user lacks self awareness of, again, underlying assumptions, context, and purpose of their own communication (and subsequently blame the bot of participating in some kind of conspiracy or otherwise being unintelligent, or generic).
All to say that while the job title of "prompt engineer" may be short lived, gathering and communicating the information to either give a bot in training or teach users, is and will continue to be a highly valuable skill.
Makes me think of philosophy degrees. Virtually useless on their own, but an absolute powerhouse of a tool when paired with something else such as law, business, or other industry involving people and thinking.