Originally Posted by Gamer Escape Interview with Koji Fox (Fan Fest Vegas)
Koji: Basically it’s all a matter of length of worship. With primals, it’s all about how you have someone worshiping you and you become that primal and they believe in you and you get your power from that. For the Ixal or the Amalj’aa, it’s the belief that makes the aether combine to summon forth these primals—so when you look at Ifrit, and Titan, and the one’s we’re calling primals, they’re considered very young. They’ve been believing in them for a long time, but looked at in a span of all the eras it’s not that much time. <...>
Anwyll: <...> [So,] it’s just has to do with the length of time.
Koji: Basic length of time.