Too many cooks spoil the broth

Unlike Sweden and other countries that have 1 central bank, America has 12 Reserve Banks. Even the continent of Europe has 1 central bank, the European Central Bank (ECB).

The 12 Reserve Banks and their 24 Branches are the operating arms of the Federal Reserve System. Each Reserve Bank operates within its own particular geographic area, or district, of the US lending to depository institutions to ensure liquidity in the financial system. This structure ensures that the reserves and decisions of the Fed are distributed across the country and that the conditions of communities from every part of the nation are considered when the Fed sets monetary policy.

By land area, the United States is larger than the European Union. If you add up all the central banks in Europe's respective countries and the ECB, there are significantly more than 12. This means that the US's 12 Reserve Banks are fewer than all of Europe's central banks including the ECB, despite a smaller land area.