Bitcoin is decentralized because no one party has monopoly control over the system. That DOES NOT mean that resources and influence will not coalesce around certain points (MtGox, the core dev team, etc.).
However, there is all the difference in the world between a system like Bitcoin and a system like the Federal Reserve, where one organization has monopoly power to print, manipulate, and control.
Don't confuse "decentralized" with "evenly distributed."