When you have a currency that is tradable like gold in wow, there will always be someone who will buy it and someone who will sell it. If Blizz really wanted to stop gold trading they would make it so abundant that it becomes worthless.
Blizzard no longer cares that it ruins the game. They make the situation worse by creating a market where gold is essential. They are manipulating the need for gold to gouge more cash.
The lariat recipe drop was just the never ending carrot and stick. It dropped once per month per server. Check undermine exchange for each server. There was never more than one being sold at a time. You can also check when the last one was sold.