Not really the case. More to do with infrastructure, coaching, and the people who attend Augusta. First point, you flat out need perspective, no good southern team goes to that Invitational. You don't see GTech, Florida Tech, Jacksonville, etc.... You see College of Charleston, Davidson, etc.. This isn't meant to knock anyone, it is simply acknowledging the competitive level.I'll be sure to let you know by how much, but it's because they do not erg at all.
Second point, these teams are not particularly fast because they are not designed to be fast. Most of them have minimal support from their schools, minimal coaching, minimal training, and frankly; many of them don't want to be more competitive than what they are. They have a good time, stay fit, and enjoy the outdoors.
Third point, most of the top junior/college programs exist on the west coast, mid-atlantic corridor, northeast, and a few scattered in the mid-west. As such, the presence of athletes with rowing experience is higher in these regions. Moreover, the likelihood of finding a good athlete who's willing to try rowing (due to seeing it, having family that has rowed, friends that rowed, etc...) is greater. This leads to recruiting advantages that many southern teams cannot overcome.
My point, before you use an experience of "destroying" teams to validate one training program/style over another; you should thoroughly consider all the info about what led to the results to begin with. To do otherwise is to sell yourself short as well as the people you competed against, particularly since the face of southern rowing appears to be changing lately. Good luck with your season and enjoy Augusta. If you have the chance I recommend stopping by the BolWeevil restaurant (downtown Augusta, near the river and amphitheater). Haven't been there in years, but I always remember it being pretty good and having great desserts.