Because every moment that they spend on implimenting this idea is time taken away from adding new relevant content to the game. Its kind of like them trying to revive factions because they can't figure out that 99% of the player base could give a crap less about factions. Factions don't have members because players don't want to belong to factions and nothing will change that, so they might as well spend their time on relevant content and totally delete factions.