This particular post is about a study of academics in Italian Universities who ostentatiously signal their incompetence and lack of ambition, as a survival mechanism in a competitive and patronage-dependent culture. However, I think that this is a very common social signal. We just notice it because Italian Universities have different social rules that Anglo ones. There were some comments yesterday about the people in any workplace who work very slowly and do very long hours, without showing much initiative. I believe this is a social signal of submissiveness, obedience, and deference to hierarchy.
I wouldn't be surprised if there are some kinds of physical neural issues which make some levels of competence easier for some people to perform. I hear that Usain Bolt's muscles are about 90% 'quick fire' fibres, whereas most people have a 50/50 mix of quick and slow fire. That may be genetic. However, if he hadn't devoted his life to cultivating that genetic accident, he wouldn't be the runner he is. He has chosen to be super-competent in his field.