What's really great about esports is the fluidity and relative accessibility. It isn't difficult to pick up and start practicing at a video game - whereas athletics require expensive specialized gear and/or playing field, going out and finding a dedicated team, and even then there's no clear way to enter the professional scene.

With esports all of that is simpler. You can start streaming your own games across the globe. And switching between games is far easier than switching between athletics (what are the chances you'll be able to play both basketball and football professionally? The skills simply don't transfer.) Finally, esports introduce genres and themes layered on top of the gameplay.