please also factor that its costs a lot of money, time and effort on the staff front. A lot of it is out of their pocket and personal time. So i assume the staff are tired now and want to "retire". It's what happened to us in the UK with BUCK.
What you might find is that the remaining brony cons actually become the bigger ones because bronies will never stop "conning". But I dont think the fandom is quite wanning yet. Theres a lot of communitiy celebs still, a lot of artists, the VA guests want to keep coming along and if someone is willing to take the reins, new cons will appear.
I dont think we should take BronyCon's exit as an end of the world type thing.