When a homeowner receives a notice from the bank saying that the bank is going to foreclose on his house and put it up for auction at a sheriff's sale, there is a good chance he will move out. Not wanting to see the pain of his house being taken away he may assume the house is no longer his and not want to follow what happens.
However banks don't always foreclose and the pain can be worse than if they did.
Eventually bills and fines will find the homeowner. When the house is left abandoned scavengers may pick it clean and needed repairs will mount. The owner will likely have mounting bills from the mortgage, utilities, taxes and fines for violation of local housing codes.
The homeowner becomes like an indentured serf with responsibilities for his property but with no way to benefit from it.
Banks have found that they can reap benefits by selling the unpaid debt to debt collectors, from insurance, from tax and accounting benefits without the costs and responsibilities of ownership.