The people CAN afford the mortgage payments at the sub prime level they signed up for. What they can't afford is the premium interest rate that kicks in later. You can pretty much bet that most people enrolled in those programs are unfamiliar with compound interest and mortgage calculations so they were convinced by predatory mortgage salesmen that they could indeed afford to own their own home.
I'm equally sure that most of these sharks knew that the mortgagor would foreclose on many of these poor families shortly after the higher rate kicked in. The whole scheme collapsed because the bottom fell out of the housing market. It was no longer profitable for lenders to foreclose, kick the people out, sell their house and pocked all money owing plus hefty penalties.
The bailout is for rich mortgage lenders. The people losing their homes are the victims.