Notice all the red bars on this chart, they are recessions. Prior to WW2 there were recessions every couple years in a boom-bust business cycle where the wealthy would be able to pump up credit in a area, and when the people would start their businesses and build their buildings, the banks would get a run and go bankrupt killing the economy so the wealthiest people could swoop back in and buy up all that newly built capital.
The Federal Reserve System and our monetary system has not only decreased the number of recessions but also their duration. The checks and balances are only possible with it, and it doesn't cost us a thing to have because the banking industry is what pays for its usefulness to us (like the FDIC insurance).