Shut down? No. Bring in line with everything else in game. Not strictly in terms of loot, but in terms of the overall cost v reward. that doesn't preclude runs that are higher on the loot reward and lower on the XP reward, but there needs to be balance.
And yes, it effects everyone that you play with if you have have access to a warehouse of loot. It changes the expectations placed on every other player in the game. It effects the overall game economy if those items make it to the AH.
Look, if one person has uber loot, yeah, no big deal. If a population does it throws off the balance in the game.
And frankly, if everyone in game has all of the uber loot coming out of their noses the enemy has to be balanced to deal with that. that is what we call Monty Haul and I thin tkeh vast majority of folks have played MMos that have ended in the land of Monty Haul... it ain't fun.