Or you live completely within your means which is hard for many people. Credit makes the world go 'round.
Problem is, that banks issue credit and they lend it out with very high loans to capital ratios. So if the bank fails, then everyone goes to withdraw their money, everything goes to hell. The economy hangs by a thread on these banks.
In the past, governments have actually made laws forbidding people to withdraw their money.
It's a huge scam, really.