Dragoncon is more than 15 times the size of Worldcon.
Comparing them is apples and oranges
---Dragoncon is a full spectrum media con focusing on gaming
--Worldcon is a literary convention
--Dragoncon is professionally run
--Worldcon is entirely volunteer
--Dragoncon is in one place, every year
--Worldcon moves around from place to place.
World*Con is so small after all these years because of its exclusionary practices, nasty attitudes, and institutional racism.