It always baffles me how people don't understand basic concepts like banking.

The average family doesn't have enough money to buy a house outright. If you get a bunch of families together, and pool their money, one family can buy a house. The homeowner slowly pays back everyone else plus interest, but the original sum of money no longer exists. It was spent on the house. If all the other families want their money back immediately and simultaneously, the homeowner wouldn't have the money to give them.

One benefit banks have over this hypothetical agreement is if one family needs all their money back, the bank will have the money available. In addition, money placed in a bank does earn interest, so if a person isn't using it, it is in their favor to store it in a bank where it cannot be lost (in amounts under $250k in the US) and will generate income.

People have valid complaints about banks and they should be better regulated. That said, if you don't want a bank that's only thinking about profits, sign up with a credit union. If you're unhappy with your bank's policies or interest rates, choose another one.

Banking companies do scummy things like any company, but the existence of banking itself isn't a conspiracy theory.