Excellent graph below from Chris Whalen showing the net interest income for U.S. banks (grey line) is relatively unchanged since the financial crisis hit in late 2008. However, their interest expense has dropped by over $100 billion during that period (yellow line). Why? Banks are now paying individuals $100 billion less every year due to the Fed's zero interest rate policy.
This is how savers have been crushed and why retirement savings has transferred into the hands of U.S. stock market speculators desperate for yield.