Today’s xkcd comic is a classic but sadly is a bit weak on economic science.
While I would like to think that economics could expose supernatural myths, the underlying logic in this cartoon is flawed. The logic is that if X is possible, then Y would be very profitable. The problem is that X is either (i) a skill held by a few individuals or (ii) widely accessible knowledge.
If (i), then the people holding the skill would earn all of the rents. You would see the economic profits in their wages and not in the profits of those who employ them. You might argue that we don’t see high pay to dowsers etc. I have to, of course, remind you that you have to take the individual fixed effect into account and demonstrate that someone who purports to be a dowser would be earning about the same wage in another activity. Given that they are likely morons, you can draw your own conclusion on the super-normal wages they might be earning; it is possibly surprisingly high.
If (ii), many firms will have access to the knowledge and so no firm using the knowledge would be making a “killing.” Indeed, for relativity and quantum physics that is exactly the case.