Can you please show some figures to back up these statements? It's really hard to believe your comparisons without statistical figures. Personally, I don't think you can even compare the two circuits. It's like saying that the Major League ticket sales are not growing at the same rate as community soft ball. Two completely different types of fans (even though some of that fanbase may be shared). Also, two very different types of ticket prices (if some community softball events even have ticket prices at all).
Lets be real here, DCA crowds are by in large people who are connected to the DCA activity. DCI crowds, while still largely made up of people from within the activity are also made up of actual "fans" from outside of the activity. Example, a huge number high school band students in America cannot WAIT for that "local DCI show" in their area. However, very few (in many or any at all) have the same drive to go to a local DCA show. It's just not where their interest is. Frankly, me neither. Not that I have a problem with DCA. I think it's great for those involved. I'm just more interested in DCI World Class and if I have to choose between one or the other, the money inside that very tight budget of mine is going to be spent on DCI, not DCA. Nothing personal. I just don't have a vested interest in DCA at this point in my life. Neither do I for DCI either, and that's the difference. DCA crowds are largely made up of those who have a vested interest. DCI crowds have that PLUS those who don't.
All of that to say, I think you are grasping at straws with your statements. But I'll eat my words if you can show me some figures.