The thing is, it's four years between Olympics. That's a long time. A runner can go from his prime to his decline in less time than that. Four years ago (actually five) Kipchoge won so easily that probably most thought a repeat would be a no-brainer. But this past fall he lost badly and now the chances of him winning the Olympics are uncertain. This is the GOAT we're talking about. For Rupp, who is far from the GOAT, chances are even more uncertain.