Most of the Jobs aren't actually one of a kind. They're more like lost/uncommon/elite arts. WAR and DRG for example are elite, but they're still made up of entire communities. The only special thing about DRG in particular is the Eye of the Dragoon, which sets one DRG apart from the others. All of the elder Seedseer's (Padjali) Even their relic weapons are seen being used as the standard arms for the Job.

I honestly think what one guy said way back in the beginning of this, that the class system would simply stop being really acknowledged, is pretty acceptable. It's useless, most everyone knows it, it's there, it's whatever.