Congress has the power of the purse, and can keep the executive branch on a very short lease if it chooses. Meantime, subjects of an investigation can often borrow a tactic from civil litigation and bury the other side (in this case, the DoJ) with heaps of irrelevant or incidental material that will be enormously time-consuming to sort through.
Partly because of Congressional funding decisions going back for years and partly because of inefficiency, government legal investigators are badly lacking in the technical department. Sadly, this state of affairs suits some people very well.
It is hard for me to believe that if Eric Holder and/or Barack Obama were loudly saying "Wall Street is getting away because you aren't giving us funding", things would not change.
... I think the "suits some people very well" part is most to the point. It is hard not to imagine that this group includes those at the highest ranks of government.
Edit to add reference: http://www.justiceatstake.org/newsroom/press_releases.cfm/ca...
No, I don't make this stuff up.
At what point do the claim "they are doing their best" and the claim "clearly they don't have the resources to do anything" collide and explode into burning rubble?
I can believe that there are many noble individuals in the Doj who are doing their best. But how can one not call a resource-less investigation a tooth-less investigation if you are talking about intentions of Doj itself?