Trying to compare athletes from different sports is pointless.
That said, there were some atheletes that were so far "above the norm" that they are widely recognized as "best" in their sport by many.
For basketball, it was Michael Jordan, for hockey Wayne Gretzsky, and for golf Tiger Woods. Arnold could be said to be that superstar for bodybuilding, but his status is as much the result of his personality as his physique.
Baseball and Football really don't seem to have any single individual that is their one "Superstar" the way the above sports do.