You have to realize here that the "reward" for taking an "in demand" job to a dungeon is so incredibly trivial you might as well not take it at all. The only bonus you get is a 50% gil bonus on completion, not even during the dungeon. Which roughly means that if you finish Castrum Meridium for instance, you get 1500 gil off the boss, and an extra 750 gil on top of that for being either Tank or Healer if that job was in demand.

Those amounts of gil would have been fine, were it not for the massive amounts of balant hacking and exploits that were used to generate billions in the first week alone that ruined the economy ever since.

Not to hang on to 1.0 times, but gil rewards used to be 10x this. They cut everyone's gil (and all the quest payouts) by 9/10th so it would make things more fair. Which is a nice concept, were it not that the amount of gil introduced in the first week from above mentioned exploits made any and all quest/dungeon reward seem trivial and not worth it at all.