This is my personal opinion based on reading history and current event articles.
The Occupy Wall Street movement is protesting a number of issues, but the primary one that links all the issues together is the death of democracy that started with the Declaration of Independence and the Revolutionary War.
The cause of death is the spectacular success of unfettered and loosely regulated capitalism. The politicians in Washington who were supposed to protect the Constitution and our democratic way of life have become slaves to the money faucet that capitalism has turned on in the form of lobbyists and campaign donations.
Our democratic system has been replaced by an oligarchy of money and influence.
While this change has been going on for a number of years, perhaps starting as long ago as 1776, the change process completed under Bush and Cheney, who are part of the oligarchy, and it took several years before we got the full impact.
The oligarchs are powerful leaders in the energy, drug, defense, banking and other major industries. They dictate policy to their bought Congressmen and the oligarchs expect their congressional minions to implement the demands. This means that all legislature passed in Congress is tilted to favor the oligarchs thus making their hold on the country even stronger
How do we take back democracy? I don't know the answer, but we can't expect Congress to turn off the money faucet by itself.
Some partial answers are to overturn the Supreme Court's ruling that corporations are people with a right to free speech (I.e. campaign donations). Lobbyists must be strictly regulated or even banned. A giant step in the right direction would be to institute strict term limits on Congress. A wave of fresh blood makes it much harder and expensive for the oligarchs to control Congressmen who are constantly getting replaced. They would be reluctant to fork over money to a Congressman who will soon be out of a job.