This post is half-baked, and is perhaps just non-sense, but hear me out for a bit.
If there is a useful skill that can be defined precisely, then any competitive economy will converge to a point where that skill can be outsourced. This means the highest paid employees will always be the ones with the most vaguely defined skills.
People go on and on about why CEO’s get so much money even though what they do is not even very clear. The ambiguity of their skillset is perhaps the reason why they get paid so much.