Need glasses? you seem to be a bit short sighted.

With a competition like this, you get people watching matches. The more spectators there are, the more mainstream the game is, which brings sponsors (evident in the difference between the sponsors of nGRi and this) the more sponsors/quality of the sponsors, the more competitors will want to join, as it is obviously important enough for them.

In short, big comp for big teams, big sponsors, more comps for lower teams.