Raven, I think this goes back to the mid 2000's when ADV was really picking up speed. It seemed that every week-end there was a new "ADV national rally" popping up, and every ADV rally was getting a little watererd down. So the mods picked a few of the larger ones around the country and made them the official ADV rallies.
There are lots of get togethers for ADV riders, but that does not mean that they should all be an "annual rally"
You are spot on with your interpretatation of what differentiates the Annual rallies form just another bike(trailer) week.
Good for the mods and Chris for sticking to their guns and keeping the Annual Rallies purely for and by ADVriders
On a side note, be careful what you wish for. I usually go away from every ADV ride thinking "Man this should be a National" then I think "Nah too much of a good thing is just too much" At my first Eastern (Ricks) Rendezvous there were about 20 riders, it's grown to over 200 now, and will be bigger this year. Westfest 2013 took 6 months to organize with I'm sure countless headaches. Thanks again to COXR650L and family for all the hard work.