I don't have much proof, but a theory that fits the facts pretty precisely. Antheria occurred while the giant rift between the "East Coast"/AC conrunners and the West Coast people.
(A quick aside for those who don't know: a part of AC's reason for existing was the genuine depravity of Confurence (in LA), and Kage didn't like that. Later on, there was a silly slapfight involving stage time at Further Confusion for Kage, and then there was a serious chill between AC and the then-whole Pacific Timezone con scene.)
So, 2 moved from somewhere in the Midwest to LA, Confurence/Califur's backyard. And he and Kage were ultra-tight. So, this con was started. For a first-year con the hotel was very impressive - there were some rumors that was because words were put in for them by the AC crew. (Also this was kind of their downfall...) The GoH lineup was *intense*, including Stan Sakai, who at the time was the biggest 'score' AC ever had - and the guy who was the first major 'pro' outreach to get other industry people to not think AC was a bunch of freaks. The con also had this whole 'anthro evolved' thing going on, billing itself as a whole new level of refinement in conventioning - again, pride before the fall.
So you had AC people probably going to bat to jumpstart the con, you had them supplying a GoH corps that no first-year con would've been able to pull on their own merits, and you had a palpable attitude of 'we're doing this right', at a time when AC hated the California teams. The simplest explanation is that 2 wanted a vanity con and Kage et al were all too eager to go along to finally show up the land of Mark Merlino. Then, when it failed pretty embarrassingly, there was a sort of Detante with FC - Kage showed up to a solid 'meh' from the congoing public. At the minimum it was mutual self-interest. At the most? They were trying to expand the empire.