Just because it artificially extends the life of the content doesn't mean it's a good system though. If that is the true intention then they're simply trying to stretch short content with awful drop rates. Not a good way to go about it IMO.
At the very least, if they do nothing else, they should tweak the system so that if a player gets a drop that they already have, it is put into their loot list instead so that they may pass it to another player.