Banks need to make money.
They have to loan out the cash deposits of their clients in order to do so.
If banks cannot accrue wealth through debit fees or high loan interest rates, they will collect revenue from more controversial, though still common, sources.
Many banks charge ten cents a month for every checking account with less than $10,000. Washington Mutual did something similar before going under. Still, most banks struggle to remain solvent.
No wonder more clients are removing their deposits from large commercial banks. No wonder more depositors are seeking out credit unions, who offer higher interest rates for savings and checking accounts while providing a sound foundation and backing for clients' monies.