Credit Losses as a Result of Debt Resale to Remote Investors?

There's a common view that had debt been held by the originators, their incentives would have kept them from making bad loans. No theory is offered as to why the ultimate holders didn't have an incentive also to avoid extended credit unwisely, thought they might not have known they didn't have enough knowledge. But how do we explain Countrywide, Citi, Merrill Lynch, etc? How many mortgage originators are bankrupt?