Earlier quoted context omitted.
I’m reminded of those pro StarCraft players who retire at like 30 because, while their strategy is perfect, their fingers simply can’t click or hotkey as fast as the twenty somethings.
I imagine it is the same for any elite level sport. Except perhaps chess.
That is why when Rausis(https://www.chessgames.com/perl/chessplayer?pid=14248) rating was approaching 2700 in his 50s everyone was very suspicious.
It is partially due to the incredible levels of stamina required to stay on top of the game for 4-6 hours.
Also as Kramnik said when he was retiring, you start making strange(read wrong) decisions suddenly.