It's much like asking which came first, the chicken or the egg? NDA and St. Henry are volleyball powerhouses...which is attractive to other strong volleyball players. Success breeds confidence which breeds success...and so on.
I agree that there is no doubt it's beneficial to play at a young age. On the other hand, two of Dixie's strongest players Leah Metzger and Perrin Long didn't play volleyball until 4th and 6th grade respectively. While they are athletic, more importantly they have an amazing passion for the game and are willing to sacrifice more than most for an opportunity at greatness. Those critical elements can't be taught through instruction, but rather possibly modeled by their parents or maybe it's just something that they are born with or likely both. I'm not saying waiting until 4th or 6th grade is ideal by any means, but where there is a will, there is a way.
If you look to girls basketball, Highlands has beaten St. Henry the last 200 years or so:) If St. Henry takes the same approach in basketball that they do volleyball will they start beating up on Highlands? IMO Highlands has basketball and football in it's blood. St. Henry has volleyball in it's blood. NDA just has a lot of blood, for now.