Everyone who is not a farmer or a miner is ultimately a "middleman." Yes, even the tradesmen fixing cars and HVAC system, much less lawyers, bankers, and politicians.
Ultimately, is only the great bounty of the earth, giving us a surplus of food and raw materials, that makes human civilization possible.
a) One can only mine from in-between above/below, hence digging below and bringing above.
b) Farm/firmus/bher - "to hold firmly"...only in-between flow (inception towards death) can form (life) hold onto anything else.
c) Being implies each medium/medius - "middle" within all input, hence each ones choice within all balance.
A trade implies ones consent (to buy) trading for another ones suggestion (to sell)...hence selling self out, when buying into. This tempts one to ignore ones position as medium by selecting a chosen one to mediate all media for one.
All gives ongoing loss; each one within implies temporary growth struggling to sustain self during ongoing loss. Few suggest surplus (more than all) to tempt many to sell each other out for less and less and less....
Example: All implies inception towards death for each ones life. The suggested surplus "afterlife" tempts one to seek more than given, which devalues the life one lives exponentially, which in return permits those who suggest surplus, to also grow insufficiency into limitations and scarcity.