Good point, but you kind of miss the point. Some sports, like road cycling, have been all but reduced to one variable (how many W/kg can you produce?). Turning yourself into the world’s best road cyclist is a grim slog at the border of overtraining and starvation. Even more complex ones require serious dedication and sacrifice.

But at that point they’re jobs or obsessions. They’re something you do because you must, not because you enjoy it.