They base their profits on people who stores their funds in the bank unlike bitcoin, people who stores money in the bank's system actually let the bank holds their funds, and they can simply do whatever they want with their customers funds, even if involves investing people's money even though they don't have more money to cover that.

Not only that, they receive money from loaning money to people( even though most of the money that they loan to people they don't really own), and they receive tons of money from covering interests.
They work with credit card companies and they get interest % for processing payments.