Why don't banks not rent out instead of paying for preservation?

When a home is foreclosed and noone pays the bank for it, the bank pays a company to preserve the house untill a buyer is found. They like mow the lawn and drain out the water pipes so the water doesn't expand when it freezes and break the pipes and appliances. Instead of paying for preservation, why don't banks rent the house out untill a buyer is found? Even if the bank rented the house out for $100 a month, they'd be making money instead of losing money paying for preservation.
If renters break someting, they're liable for it. Yes, It's probably harder to sell a house that people are living in as opposed to a clean one buyers can move right into, but probably most homes are sold while lived in, or the bank can just have it cleaned before they move in.