In a traditional securitization, a special purpose vehicle sells securities backed by a loan pool and uses the proceeds to purchase the loans from the bank. There might seem to be no problem with this arrangement, as long as banks shed the risks that go along with the loans.
If this were the case, securitization would simply be a device for shifting to the capital markets the risks associated with the bank loans securitized. Banks would then continue their traditional role of originating the loans, but the capital markets would play an increased role in the funding of the loans.