Low rates compared to what? Wall Street banks?

Lenient default terms compared to what?

Government assistance for the borrowers in what form?

And stacked against the borrowers due to the rapacious secondary market servicers. More money can be made off late fee and penalties than off simply servicing the loans, so they do everything in their power to make that the case, including misdirecting funds, misstating loan amounts, requiring burdensome documentation, while at the same time setting penalties on accounts.