People don't realize that it's in human nature to change. People change, generations change, priorities and lifestyle changes. Deep down, though, rotten nature stays the same.
It's silly and very stupid to think how SL would make younger people watch football instead of playing Fortnite, LoL, PoE, DOTA, WoW or any other game. E-sports sadly is becoming a new thing and it attracts a lot of people from which majority is young. Those aren't interested in football, those are gamers, they hardly care about anything bar video games and close set of friends. Even with SL I'd bet maybe 2-3% of those would care about the competition. But more than 2-3% of the current fanbase wouldn't even watch SL.