What do you mean "old stuff"? You do know there was content before the Cataclysm expansion right? And you do know that Cataclysm Gems/Enchants/... come with level-limitations?
There will always be min-maxers that want the best for their characters (or alts) all the way leveling up to 85 (soon to be 90)
How can that make me a decent amount of profit per day? ^^Many small amounts add up to one big pile of gold, if one American gave you one dollar, you wouldn't be rich, if every American gave you a dollar ...