Originally Posted by GuitarBizarre

1 - Pros in the most popular games practice 14 hour days to be at the top of their fields.
2 - The most popular games have professional teams who manage and run contracts for their major players.
3 - Sponsorship exists, and on a very wide scale. Evil Geniuses, a single team, for example, are sponsored by Intel, SteelSeries, Monster Energy, Kingston Technology, InWin, Beyond Gaming, Sapphire Technology, Six Pool Gaming, Bigfoot Networks, Intel Extreme Team, GUNNAR Optiks, SLAPPA, and SPLIT REASON.
4 - The top players are as much celebrities within their scenes as in most other sports. I'm not talking like Soccer or Baseball, which are culturally huge, but any smaller sport like Snooker or Curling or whatever, they have their own stars that are respected, and so does eSports.
5 - They have a spectator audience of people who DON'T play the game themselves. Barcrafts are a global thing and they're frequented by plenty of people who don't play and can't play, but who love to watch.
6 - There is real depth to the games that attain status as eSports. Starcraft Broodwar, for example, is still developing as players discover new strategies and tactics to this day, 10 years after its release and 2 years after the release of its sequel (Which is currently exploding in popularity)