It seems like Cerberus was a major hindrance during the war. But they shouldn't have tons of resources after rebuilding Shepard and the Normandy SR2 (at least, we're told how much of an investment drain that was).

So during ME3, couldn't the combined resources of the Shadow Broker and all of the Terminus forces lead by Aria be enough to bog down the Illusive man? Sure, the Illusive main has plenty of contacts and resources still, but so does the Shadow Broker and Aria. Why does Shepard have to deal with them (outside of the citadel attack)? You would think that the combined forces of all the merc bands under Aria and all of the Shadow Broker's forces can at least tie Cerberus up for the duration of the war.

So why?