Some of this is just the plot/screen play mechanics, but it's also somewhat an indictment of how the FBI works, slowly and slowly build cases, offer more and more deals to sometimes murderers, all in the hope of a major RICO indictment that secures their status and career, an makes big headlines.
and also, I think it was sort of commentary that everyone are just people. FBI, whatever they are, they make mistakes, they get lazy, self serving, arrogant.
