You don't get it. There's a difference between a legitimate business and a Ponzi scheme. A Ponzi scheme is doomed to failure because the ONLY source of repayment is recruiting more investors. A bank's source of profit is the spread between interest paid to depositors and interest received from borrowers. If you think that there's no difference, you would be indifferent between a nice $10,000 balance at your local bank and $10,000 given to pyramid scheme.