It's not as big as the GBO, because it is later in the year, and kids first week of school, etc.....end of summer vacations.....the people from the Olympics are still suffering jetlag.....
Just wait there may be some Oklahoma sign-ups. But Emporia is a destination location only when it makes sense, and there are a lot of other events that people played in the Summer, so its tougher to fill this time of year. Now after September and October it gets a little easier, but people go back to school, etc, so you see a more regionalized crowd than you do earlier.
Too many people going to a far superior event... *cough* LDOX *cough*
Of course this could be the more realistic reason though....