This fact is part of the money system. When a loan is taken out from a bank, the principal of the loan is created, but the interest is not. This creates a competition in the economy to get the money that is not created to pay back the interest on the loans where some people can and some people cannot. Defaults are inherent to the monetary system as it is currently implemented. See "The Money Fix" (documentary) for the best explanation of this process that I have seen.