Although highly improbable, you can not rule out the possibility these people exist. Definitely nothing to get your panties in a knot about.
As a young kid, talking 7-9, when ever we were getting ready for the annual track and field day, the teacher would always use my long jump form as an example of "air walk". I was good in a lot of track events, quite good. But, I lived in a small shitty town with no coaching or track programs.
What if I would have grown up in a larger centre with proper coaching, training, etc? I could be a gold medal olympian. But, that support was not available, and it was just a fun thing to us kids.
There are people out there that have incredible natural ability. This ability may not be fostered to it's ultimate growth potential. So yeah, there are people out there that may be the best in the world at something, but for various reasons have never realized this potential.
Or, perhaps have realized this potential, but because they do it for themselves, have no desire to display it. It is also fact that Jordan did not make his high school team. What if this would have deterred him from ever picking up a ball again? We all know it didn't happen this way. He practices his god damned ass off. It was his hard work and dedication that got him to the level he achieved.
Too many variables to consider. No one can be sure one way or the other. I don't understand why this is such a touchy topic for some.