Why doesn't everyone use aetherytes?
To traverse the Lifestream safely with Teleport and Return requires a great deal of spiritual energy, known as anima. While many individuals, such as adventurers, possess the fortitude to endure such travel, some individuals do not. What’s more, even if one has the ability to use aetherytes, the frequency with which one can do so varies. In essence, for some, the recast time for these spells can be far longer than for an adventurer.
As a result, only a fraction of the populace can utilize aetherial travel habitually, which is why chocobos, airships, and other forms of transportation still play a major role in Eorzea.