Because the REWARDS aren't better. I don't see how this concept isn't getting through to you. You want me to expend an hour running a dungeon for gear I don't need. And being r30 is completely cosmetic when it is only so I can run through one r30 dungeon on a r50. I don't need the 'prestige' of a r30 dungeon and I don't need the 'gear' from a r30 dungeon, hence for a r50 it is completely cosmetic putting a false cap on your character.
