I don't really think it was a sweeping statement at all. HS marching bands have become very very good and I do agree that in terms of quality there is some overlap with the top of the HS marching band activity and DCI world class. However the top groups in DCI, and we can argue how far down that extends (top 6? 12? 17?) are quantitatively better than even the best HS bands. The designs are more sophisticated and intricate, the technique across all sections is at a higher level, more demanding and of a higher quality of performance and so forth. It comes down to performer maturity. 13-17 year olds who are in a band because they live in a specific district just cannot compete with 19-21 year olds that are hand picked out a large audition pool. That isn't a swipe or knock on HS marching band that is just cold hard reality.