The difference with American Football is although there have been subtle changes in the rules, it has been mostly the same for over 50 years. With esports (like in the case of Overwatch) they do not have that lifespan. So unless you are someone who is currently playing that game, you don't know how it works really. And if you were someone once playing that game 5 years ago, as in the case of Overwatch 1, they literally shut it off and it can't be played anymore.