If you are making the assumption that people do not differ at all in their capabilities, talents, aptitudes, etc., then I’m not sure what to say except “that’s very, very obviously wrong”.
If you are not making that assumption, then I can’t make sense of your comment.
In any case, even ignoring the above—as I said, I worked a retail job for some years. I know what kinds of skills that job required of me. I know what kinds of skills other jobs (e.g. writing software) have required of me. I can see that the former is not predictive of the latter, has almost no overlap with the latter, etc. These are simple observations from my own life, from which I am drawing straightforward conclusions.
I have to ask, @fasf: what do you do? Do you run your own business? Could you tell us a bit about that?