Actually I think what you're referencing is still Dunning-Kruger: "Conversely, highly skilled individuals tend to underestimate their relative competence, erroneously assuming that tasks which are easy for them are also easy for others." (from wiki)
More specifically, it's the Downing effect: "One of the main effects of illusory superiority in IQ is the Downing effect. This describes the tendency of people with a below average IQ to overestimate their IQ, and of people with an above average IQ to underestimate their IQ." (also from wiki)
I think it's a pretty good analogy. I thought it was well understood that Michael Jordan was a very competitive individual and didn't take his wins for granted and that there was always something to work towards and improve upon.
"...the most competitive individual...Always felt like somebody else was going to outwork him so he wanted to out work them." - A trainer of Jordan's. (Video for reference: http://youtu.be/w39-_rauFSk)
usually, as a shooting guard, jordan would be playing with 3 people taller than him on his own team, and only 1 person shorter than him.
just like basketball is not purely about body size and athleticism, chess is not purely about iq. And it is kind of idiotic that iq is the thing that people think must be the one thing that makes good chess players good.
after a certain point, iq probably doesn't matter. motivation, concentration, competitiveness, determination, experience, preparation, risk-taking, creativity, pleasure when thinking about chess... i really don't understand why iq is the thing that's talked about so much.
magnus clearly understands that some people will neglect chess for something else. The implication is that there are geniuses out there today doing other things instead of moving figurines over a grid... that's a very humble and wise world view.