If, and that’s a big if, he was experiencing skill and physical regression, I think it would be incredibly suspect that he had this significant amount of drop off, year over year.
I believe he has a medical issue he is challenged by.
It’s uncommon that superstars have such large drops in performance in just one calendar year.
Usually it’s more of a gradual decline, which is partly because they are so committed to their craft and highly tuned athletes that they find ways to compensate mentally, strategically or physically and are able to stave off huge drops in performance, as a result.
But we really don’t know. It’s disturbing to watch, that’s for sure.