It's just that being good at a video game is a lot less impressive than being good at a sport. Both require hand-eye coordination, quick reflexes, and teamwork, but sports takes it further because it also requires stamina, strength, and courage (to be able to play in front of a stadium filled with tens of thousands of people and not falter). Combined with the fact that sports are more active (the athletes have to move their whole bodies instead of just their hands) and the matches last longer, and it's obvious why being good at sports is prestigious, but being good at a video game isn't. Sports have all the qualities of video games and more, plus they don't require you to be a lazy bastard who sits on his ass all day, plus they keep you healthy and have an effect on your life/physical body.