Esports and sports have extremely different revenue models. The differentiator is that no one ‘owns’ traditional sport games. Anyone can make and sell a basketball, but blizzard has a monopoly on over watch. Sport leagues only indirectly make money when people play their game, but for esports it’s extremely direct and also easier to measure.

League of Legends makes multiple billions of dollars a year, not from esport receipts, but from people buying content in the game. The NFL doesn't make a dime when you play football in your backyard.