There's a difference between "playing the game" and playing the game. I can sit at a chess board and move pieces around and say that chess takes no focus because I chose not to focus
Is there thought? How do you know his skills are not due to a few hours (tens of hours, hundreds of hours) of intense training of a few basic rules, and the rest is just freeroaming like it is for every other player?
Because there are other players on the other side of the game. They will be at comparable levels of "intense training of a few basic rules" (due to ELO based matchmaking) and they will be trying as hard as they can to beat him.
You can't assume high-level players are trying as hard as they can in a proof that high level players are trying as hard as they can.
Your argument doesn't make any sense in the scenario I described.