A 'vanity' item system is planned to be added to the game eventually where you can switch one piece of equipment's appearance with another, but when that will happen is unclear at this stage. Most level 50s usually wear either 'Darklight' gear, or a combination of Artifact Armour sets 1 and 2, which is definitely not the same gear you get at the beginning, in appearance or stat wise though. I prefer AF though myself as it's the traditional appearance of that Job from past FF games.