Even in the various iterations of Superman canon, there is an endpoint.
Superman either gives his powers away, or he loses them. He either dies in battle, or simply abandons planet Earth altogether. One way or another, the various strands of the mythology find a way to intersect, reaching an inevitably human decline that we can all understand: There is a rise. And there is a fall.
And so it will go with Cam Newton — the self-ordained Superman of the NFL, who enters his 11th season still searching for one last exceptional glimmer of what used to be.