Multiplayer when?

It does because games with unrestricted trade have their drop rates balanced around the assumption that you will trade because its easier. D3 on launch & prior to the removal of the AHs with loot 2.0 was the perfect example of this. Drops at launch were aweful because of the AH, and when they removed the AH they buffed the #### out of the drop rates to compensate.

This is what happens.