My first GenCon was 1994. BT was HUGE. I mean huge. I went again 1997, 2000, 2003 (when it moved to Indianapolis), 2006, 2007, 2009, 2013, and 2014. I saw BT drop off sharply and climb back in popularity. OTOH, GC has gotten massive. So there is more of everything. The problem is, GC is too massive. Its crazy big and hotel space is incredibly hard to get and expensive next to the convention center (the facilty footprint keeps growing; wear comfy walking shoes at all time). I stopped going. But that's just my experience.