Dillard has essentially become an invitational. As the longest running KCBS contest in Georgia there are many more teams who want in than there are slots for. The space in their little town is very limited and the folks who run the event give last year's competitors first dibs on coming back before accepting applications from other teams. What openings do become available are typically filled six months in advance.
I know it's frustrating; it took us three years to get in. My advice is that you call Jane Tomlin and let her know you're willing to come in at the last minute in case there are any cancellations. If you can be prepared to go with a moment's notice there's a chance you can bag a slot in the last week if another team has to pull out for some reason.