I don't think that the intent with the Unity upkeep on leaders is 'pay'. Personally, I've thought of it as the work and effort required to keep an organization going in the same direction as more and more individuals are added to the central decision making circle, while increasing costs as leaders become higher levels represents their growing egos becoming an issue in the decision making process. But it's up to interpretation, and as stated, works alright mechanically.
And yeah, "Trade" is a happening now, no matter what we think about it or whether it serves a justifiable purpose. For this to end in any other way, someone would need to admit that they made a mistake, and it's really hard for humans to do that.