Soooo... let's boil it down.
Group 1: "I want to level outside"
-Leveling outside has sentimental value.
-Leveling outside is actually fun, compared to running around opening chests.
-Leveling outside lets one "learn" their job.
-Leveling outside allows one to get into the game if they are a newer player.
Group 2: "I want to leech"
-Leveling outside is boring and repetitive.
-Leveling outside takes much longer, prolonging the enjoyment of endgame.
-Leveling outside takes too much gil for little to no reward when given the option to leech otherwise.
-Leveling outside is old, and most veteran players are tired of it.
-One can learn their job quicker and faster, and most of the time better, by doing research into their jobs role, important stats on gear, Job abilities true effects, and the caps of their stats (dDEX, fSTR, Crit Rate Cap, Fast Cast Cap, etc).
In the end:
Group 1 caters to newer players to some extent,
while Group 2 caters to veteran players who have had Lv.75 jobs for years and are tired of it.
Considering the amount of returning players outweighs the amount of new players, SE seems to know it's demographic.