Quote Originally Posted by Leonlionheart View Post
because the player base only knows how to undercut
It is basic economics. Price is determined by supply and demand. If supply outstrips demand by enough to push the price to near or below the NPC price there is no reason to put the item on the Auction House. Clearly not enough people want this junk or its price would be higher.

Add the fact that you can only place 7 items at a time on the AH and that things like logs and ores don't stack. This is why the junk is NPC'd.