The author of an article called "Why Is It So Hard To Hold Wall Street Accountable?" is perplexed by the damage Wall St has done to society and the difficulty the US system of justice has in identifying wrongdoing and holding perpetrators to account:

"There's a clear solution to this problem: establish a new Consumer Financial Protection Agency that only cares about keeping consumers safe from predators, with the power to both write and enforce regulations on any lender. Sadly, if the FCIC can't demonstrate the OCC's outrages to the public, it's much harder to build momentum for that reform." - Zach Carter


It is not by chance, the system has been rigged, special interests and the agents of foreign powers have riddled the American political system with their people.

You must have noticed the number of outraged bills appearing in Congress with a high media profile, then disappearing without trace.

You can predict what happens at a tactical and Strategic level:

• Good reception for the latest cause of public disquiet or outrage by members of Congress: open arms, expressions of righteous indignation and solidarity with the people.

• Congressmen and women extract the maximum media advantage from the hot initiative to rein in the latest in a long line of Wall St Excess

• Wall St special interests initially play for time and let loose their ambassadors, the lobbyists.
  

• Lobbyists get to work on pliant politicians in all branches of government

• Special interests activate disruptive and disingenuous media campaigns

• Pliant politicians draw the teeth of any proposed legislation and put in policy beneficial to the special interests

• If possible delay the bill or inquiry indefinitely in committee

Strategic

• Control The Media


• Support and elevate financially those Democratic politicians who's views mirror your own


• Support and elevate financially those Republican politicians who's views mirror your own


• Control the Democratic candidate selection at national and state level


• Control the Republican candidate selection at national and state level


• Politicize national, state and local executive government through political appointment


• Politicize security services national, state and local through political appointment


• Control the courts and judiciary through political appointments


• Systematically create conventions and laws over time which make the ruling elite unaccountable.


• Disrupt the emergence of parties and leaders independent of this strategic regime

In science, you can predict outcomes, so I ask you to prove my theory, pick any important issue past or present that makes its way through the media to congress and apply the rules above. 

What I am saying is that even if there was a new Consumer Protection Agency, applying the tactical and strategic rules above how long before it would be disrupted and rendered useless.

• Think Glass-Stegal
• Think Clinton impeachment
• Think Bush-Cheney impeachment
• Think Kennedy Assassination
• Think illegal war in Iraq
• Think Israeli Nuclear weapons
• Think unaccountable Mercenaries in Iraq
• Think unaccountable Mercenaries in Afghanistan
• Think about the unconstitutional, unaccountable and yet all powerful Fed with Bernanke and Geithner still in charge.
• Think about all the CEO's of failed banks walking away with millions turning the much vaunted US capitalist system on its head.
• Think of the unemployment benefits being cut and the billions going to bankers bonuses.
• Think about the official 911 inquiry and the refusal to hear new evidence.
• Think Patriot Act
• Think retrospective immunity for illegal wiretapping.

This list is not comprehensive but hopefully it will provide some answers to your question "Why Is It So Hard To Hold Wall Street Accountable?". You are living in a political system which is progressively dumping the accountability aspect of Democracy while preserving the façade that it exists.

Its hard to know how to describe it.  Its a moderate, elected form of fascism. The interchangeability of personnel between Corporations, Military and the Government is striking. The elections are necessary merely to give a sense of participation, conditioning people to accept this state of affairs and giving them the illusion what they think matters.

Just apply the rules above.

Its interesting that 75% of Americans want all incumbents out of Congress........ With very good reason.

With few exceptions the only remarkable 'change' in Obama's administration has been dropping the pretense of change itself, the one he espoused during the election and left at the door as he entered the White house.

In the end "You get the government you deserve".